diff --git a/Telegram/CMakeLists.txt b/Telegram/CMakeLists.txt
index d071feae1..cd5431495 100644
--- a/Telegram/CMakeLists.txt
+++ b/Telegram/CMakeLists.txt
@@ -357,6 +357,8 @@ PRIVATE
     data/data_chat.h
     data/data_chat_filters.cpp
     data/data_chat_filters.h
+    data/data_changes.cpp
+    data/data_changes.h
     data/data_channel.cpp
     data/data_channel.h
     data/data_channel_admins.cpp
@@ -1046,8 +1048,6 @@ PRIVATE
     mainwidget.h
     mainwindow.cpp
     mainwindow.h
-    observer_peer.cpp
-    observer_peer.h
     qt_static_plugins.cpp
     settings.cpp
     settings.h
diff --git a/Telegram/SourceFiles/api/api_sending.cpp b/Telegram/SourceFiles/api/api_sending.cpp
index c50fa875e..6f971c43d 100644
--- a/Telegram/SourceFiles/api/api_sending.cpp
+++ b/Telegram/SourceFiles/api/api_sending.cpp
@@ -168,9 +168,7 @@ void SendExistingMedia(
 	};
 	performRequest();
 
-	if (const auto main = App::main()) {
-		main->finishForwarding(message.action);
-	}
+	api->finishForwarding(message.action);
 }
 
 } // namespace
@@ -191,10 +189,7 @@ void SendExistingDocument(
 		document->stickerOrGifOrigin());
 
 	if (document->sticker()) {
-		if (const auto main = App::main()) {
-			main->incrementSticker(document);
-		}
-		document->owner().stickers().notifyRecentUpdated();
+		document->owner().stickers().incrementSticker(document);
 	}
 }
 
@@ -323,6 +318,7 @@ bool SendDice(Api::MessageToSend &message) {
 		).send();
 		return history->sendRequestId;
 	});
+	api->finishForwarding(message.action);
 	return true;
 }
 
diff --git a/Telegram/SourceFiles/api/api_updates.cpp b/Telegram/SourceFiles/api/api_updates.cpp
index 82a835de7..70a2a370c 100644
--- a/Telegram/SourceFiles/api/api_updates.cpp
+++ b/Telegram/SourceFiles/api/api_updates.cpp
@@ -16,6 +16,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_session.h"
 #include "data/data_user.h"
 #include "data/data_chat.h"
+#include "data/data_changes.h"
 #include "data/data_channel.h"
 #include "data/data_chat_filters.h"
 #include "data/data_cloud_themes.h"
@@ -37,7 +38,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "window/window_controller.h"
 #include "boxes/confirm_box.h"
 #include "apiwrap.h"
-#include "observer_peer.h"
 #include "app.h" // App::formatPhone
 #include "facades.h"
 
@@ -828,9 +828,9 @@ void Updates::updateOnline(bool gotOtherOffline) {
 
 		const auto self = session().user();
 		self->onlineTill = base::unixtime::now() + (isOnline ? (Global::OnlineUpdatePeriod() / 1000) : -1);
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			self,
-			Notify::PeerUpdate::Flag::UserOnlineChanged);
+			Data::PeerUpdate::Flag::OnlineStatus);
 		if (!isOnline) { // Went offline, so we need to save message draft to the cloud.
 			api().saveCurrentDraftToCloud();
 		}
@@ -1582,9 +1582,9 @@ void Updates::feedUpdate(const MTPUpdate &update) {
 			case mtpc_userStatusOffline: user->onlineTill = d.vstatus().c_userStatusOffline().vwas_online().v; break;
 			case mtpc_userStatusOnline: user->onlineTill = d.vstatus().c_userStatusOnline().vexpires().v; break;
 			}
-			Notify::peerUpdatedDelayed(
+			session().changes().peerUpdated(
 				user,
-				Notify::PeerUpdate::Flag::UserOnlineChanged);
+				Data::PeerUpdate::Flag::OnlineStatus);
 		}
 		if (d.vuser_id().v == session().userId()) {
 			if (d.vstatus().type() == mtpc_userStatusOffline
@@ -1680,9 +1680,9 @@ void Updates::feedUpdate(const MTPUpdate &update) {
 						: App::formatPhone(user->phone())),
 					user->username);
 
-				Notify::peerUpdatedDelayed(
+				session().changes().peerUpdated(
 					user,
-					Notify::PeerUpdate::Flag::UserPhoneChanged);
+					Data::PeerUpdate::Flag::PhoneNumber);
 			}
 		}
 	} break;
diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index 3c7eb19f7..84ba30584 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -15,6 +15,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "api/api_updates.h"
 #include "data/stickers/data_stickers.h"
 #include "data/data_drafts.h"
+#include "data/data_changes.h"
 #include "data/data_photo.h"
 #include "data/data_web_page.h"
 #include "data/data_poll.h"
@@ -38,7 +39,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/openssl_help.h"
 #include "base/unixtime.h"
 #include "base/call_delayed.h"
-#include "observer_peer.h"
 #include "lang/lang_keys.h"
 #include "mainwindow.h"
 #include "mainwidget.h"
@@ -358,14 +358,11 @@ void ApiWrap::topPromotionDone(const MTPhelp_PromoData &proxy) {
 		_session->data().processChats(data.vchats());
 		_session->data().processUsers(data.vusers());
 		const auto peerId = peerFromMTP(data.vpeer());
-		const auto peer = _session->data().peer(peerId);
+		const auto history = _session->data().history(peerId);
 		_session->data().setTopPromoted(
-			peer,
+			history,
 			data.vpsa_type().value_or_empty(),
 			data.vpsa_message().value_or_empty());
-		if (const auto history = _session->data().historyLoaded(peer)) {
-			history->owner().histories().requestDialogEntry(history);
-		}
 	});
 }
 
@@ -422,7 +419,7 @@ void ApiWrap::requestTermsUpdate() {
 			const auto &terms = data.vterms_of_service();
 			const auto &fields = terms.c_help_termsOfService();
 			Core::App().lockByTerms(
-				Window::TermsLock::FromMTP(&session(), fields));
+				Window::TermsLock::FromMTP(_session, fields));
 			requestNext(data);
 		} break;
 		default: Unexpected("Type in requestTermsUpdate().");
@@ -606,7 +603,7 @@ void ApiWrap::sendMessageFail(
 	}
 	if (const auto item = _session->data().message(itemId)) {
 		Assert(randomId != 0);
-		session().data().unregisterMessageRandomId(randomId);
+		_session->data().unregisterMessageRandomId(randomId);
 		item->sendFailed();
 	}
 }
@@ -1065,7 +1062,7 @@ void ApiWrap::requestWallPaper(
 	)).done([=](const MTPWallPaper &result) {
 		_wallPaperRequestId = 0;
 		_wallPaperSlug = QString();
-		if (const auto paper = Data::WallPaper::Create(&session(), result)) {
+		if (const auto paper = Data::WallPaper::Create(_session, result)) {
 			if (const auto done = base::take(_wallPaperDone)) {
 				done(*paper);
 			}
@@ -1261,9 +1258,9 @@ void ApiWrap::migrateChat(
 	}
 	_migrateCallbacks.emplace(chat).first->second.push_back(callback());
 	if (const auto channel = chat->migrateTo()) {
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			chat,
-			Notify::PeerUpdate::Flag::MigrationChanged);
+			Data::PeerUpdate::Flag::Migration);
 		crl::on_main([=] {
 			migrateDone(chat, channel);
 		});
@@ -1291,7 +1288,7 @@ void ApiWrap::migrateChat(
 		chat->inputChat
 	)).done([=](const MTPUpdates &result) {
 		applyUpdates(result);
-		Notify::peerUpdatedSendDelayed();
+		session().changes().sendNotifications();
 
 		if (const auto channel = chat->migrateTo()) {
 			if (auto handlers = _migrateCallbacks.take(chat)) {
@@ -1311,7 +1308,7 @@ void ApiWrap::migrateChat(
 void ApiWrap::migrateDone(
 		not_null<PeerData*> peer,
 		not_null<ChannelData*> channel) {
-	Notify::peerUpdatedSendDelayed();
+	session().changes().sendNotifications();
 	if (auto handlers = _migrateCallbacks.take(peer)) {
 		for (auto &handler : *handlers) {
 			if (handler.done) {
@@ -1602,9 +1599,9 @@ void ApiWrap::applyLastParticipantsList(
 	//} else {
 	//	channel->setMembersCount(availableCount);
 	//}
-	Notify::PeerUpdate update(channel);
-	update.flags |= Notify::PeerUpdate::Flag::MembersChanged | Notify::PeerUpdate::Flag::AdminsChanged;
-	Notify::peerUpdatedDelayed(update);
+	session().changes().peerUpdated(
+		channel,
+		(Data::PeerUpdate::Flag::Members | Data::PeerUpdate::Flag::Admins));
 
 	channel->mgInfo->botStatus = botStatus;
 	fullPeerUpdated().notify(channel);
@@ -2008,9 +2005,9 @@ void ApiWrap::stickerSetDisenabled(mtpRequestId requestId) {
 
 void ApiWrap::joinChannel(not_null<ChannelData*> channel) {
 	if (channel->amIn()) {
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			channel,
-			Notify::PeerUpdate::Flag::ChannelAmIn);
+			Data::PeerUpdate::Flag::ChannelAmIn);
 	} else if (!_channelAmInRequests.contains(channel)) {
 		auto requestId = request(MTPchannels_JoinChannel(
 			channel->inputChannel
@@ -2038,9 +2035,9 @@ void ApiWrap::joinChannel(not_null<ChannelData*> channel) {
 
 void ApiWrap::leaveChannel(not_null<ChannelData*> channel) {
 	if (!channel->amIn()) {
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			channel,
-			Notify::PeerUpdate::Flag::ChannelAmIn);
+			Data::PeerUpdate::Flag::ChannelAmIn);
 	} else if (!_channelAmInRequests.contains(channel)) {
 		auto requestId = request(MTPchannels_LeaveChannel(
 			channel->inputChannel
@@ -2057,7 +2054,9 @@ void ApiWrap::leaveChannel(not_null<ChannelData*> channel) {
 
 void ApiWrap::blockUser(not_null<UserData*> user) {
 	if (user->isBlocked()) {
-		Notify::peerUpdatedDelayed(user, Notify::PeerUpdate::Flag::UserIsBlocked);
+		session().changes().peerUpdated(
+			user,
+			Data::PeerUpdate::Flag::IsBlocked);
 	} else if (_blockRequests.find(user) == end(_blockRequests)) {
 		const auto requestId = request(MTPcontacts_Block(user->inputUser)).done([this, user](const MTPBool &result) {
 			_blockRequests.erase(user);
@@ -2079,9 +2078,9 @@ void ApiWrap::blockUser(not_null<UserData*> user) {
 
 void ApiWrap::unblockUser(not_null<UserData*> user, Fn<void()> onDone) {
 	if (!user->isBlocked()) {
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			user,
-			Notify::PeerUpdate::Flag::UserIsBlocked);
+			Data::PeerUpdate::Flag::IsBlocked);
 		return;
 	} else if (_blockRequests.find(user) != end(_blockRequests)) {
 		return;
@@ -2269,7 +2268,9 @@ void ApiWrap::updatePrivacyLastSeens(const QVector<MTPPrivacyRule> &rules) {
 		} else {
 			user->onlineTill = 0;
 		}
-		Notify::peerUpdatedDelayed(user, Notify::PeerUpdate::Flag::UserOnlineChanged);
+		session().changes().peerUpdated(
+			user,
+			Data::PeerUpdate::Flag::OnlineStatus);
 	});
 
 	if (_contactsStatusesRequestId) {
@@ -2278,7 +2279,7 @@ void ApiWrap::updatePrivacyLastSeens(const QVector<MTPPrivacyRule> &rules) {
 	_contactsStatusesRequestId = request(MTPcontacts_GetStatuses(
 	)).done([=](const MTPVector<MTPContactStatus> &result) {
 		_contactsStatusesRequestId = 0;
-		for_const (auto &item, result.v) {
+		for (const auto &item : result.v) {
 			Assert(item.type() == mtpc_contactStatus);
 			auto &data = item.c_contactStatus();
 			if (auto user = _session->data().userLoaded(data.vuser_id().v)) {
@@ -2286,7 +2287,9 @@ void ApiWrap::updatePrivacyLastSeens(const QVector<MTPPrivacyRule> &rules) {
 				auto newOnlineTill = OnlineTillFromStatus(data.vstatus(), oldOnlineTill);
 				if (oldOnlineTill != newOnlineTill) {
 					user->onlineTill = newOnlineTill;
-					Notify::peerUpdatedDelayed(user, Notify::PeerUpdate::Flag::UserOnlineChanged);
+					session().changes().peerUpdated(
+						user,
+						Data::PeerUpdate::Flag::OnlineStatus);
 				}
 			}
 		}
@@ -2429,15 +2432,15 @@ void ApiWrap::applyAffectedMessages(
 void ApiWrap::saveCurrentDraftToCloud() {
 	Core::App().saveCurrentDraftsToHistories();
 
-	for (const auto controller : session().windows()) {
+	for (const auto controller : _session->windows()) {
 		if (const auto peer = controller->activeChatCurrent().peer()) {
-			if (const auto history = session().data().historyLoaded(peer)) {
-				session().local().writeDrafts(history);
+			if (const auto history = _session->data().historyLoaded(peer)) {
+				_session->local().writeDrafts(history);
 
 				const auto localDraft = history->localDraft();
 				const auto cloudDraft = history->cloudDraft();
 				if (!Data::draftsAreEqual(localDraft, cloudDraft)
-					&& !session().supportMode()) {
+					&& !_session->supportMode()) {
 					saveDraftToCloudDelayed(history);
 				}
 			}
@@ -2473,7 +2476,7 @@ void ApiWrap::saveDraftsToCloud() {
 			flags |= MTPmessages_SaveDraft::Flag::f_entities;
 		}
 		auto entities = Api::EntitiesToMTP(
-			&session(),
+			_session,
 			TextUtilities::ConvertTextTagsToEntities(textWithTags.tags),
 			Api::ConvertOption::SkipLocal);
 
@@ -2709,7 +2712,7 @@ void ApiWrap::requestAttachedStickerSets(not_null<PhotoData*> photo) {
 			Ui::show(Box<InformBox>(tr::lng_stickers_not_found(tr::now)));
 			return;
 		} else if (result.v.size() > 1) {
-			Ui::show(Box<StickersBox>(&session(), result));
+			Ui::show(Box<StickersBox>(_session, result));
 			return;
 		}
 		// Single attached sticker pack.
@@ -2827,7 +2830,7 @@ void ApiWrap::refreshFileReference(
 	origin.data.match([&](Data::FileOriginMessage data) {
 		if (const auto item = _session->data().message(data)) {
 			if (item->isScheduled()) {
-				const auto &scheduled = session().data().scheduledMessages();
+				const auto &scheduled = _session->data().scheduledMessages();
 				const auto realId = scheduled.lookupId(item);
 				request(MTPmessages_GetScheduledMessages(
 					item->history()->peer->input,
@@ -2865,16 +2868,16 @@ void ApiWrap::refreshFileReference(
 			request(MTPmessages_GetRecentStickers(
 				MTP_flags(0),
 				MTP_int(0)),
-				[=] { crl::on_main(&session(), [=] { local().writeRecentStickers(); }); });
+				[=] { crl::on_main(_session, [=] { local().writeRecentStickers(); }); });
 		} else if (data.setId == Data::Stickers::FavedSetId) {
 			request(MTPmessages_GetFavedStickers(MTP_int(0)),
-				[=] { crl::on_main(&session(), [=] { local().writeFavedStickers(); }); });
+				[=] { crl::on_main(_session, [=] { local().writeFavedStickers(); }); });
 		} else {
 			request(MTPmessages_GetStickerSet(
 				MTP_inputStickerSetID(
 					MTP_long(data.setId),
 					MTP_long(data.accessHash))),
-				[=] { crl::on_main(&session(), [=] {
+				[=] { crl::on_main(_session, [=] {
 					local().writeInstalledStickers();
 					local().writeRecentStickers();
 					local().writeFavedStickers();
@@ -2883,7 +2886,7 @@ void ApiWrap::refreshFileReference(
 	}, [&](Data::FileOriginSavedGifs data) {
 		request(
 			MTPmessages_GetSavedGifs(MTP_int(0)),
-			[=] { crl::on_main(&session(), [=] { local().writeSavedGifs(); }); });
+			[=] { crl::on_main(_session, [=] { local().writeSavedGifs(); }); });
 	}, [&](Data::FileOriginWallpaper data) {
 		request(MTPaccount_GetWallPaper(
 			MTP_inputWallPaper(
@@ -2902,7 +2905,7 @@ void ApiWrap::refreshFileReference(
 }
 
 void ApiWrap::gotWebPages(ChannelData *channel, const MTPmessages_Messages &result, mtpRequestId req) {
-	WebPageData::ApplyChanges(&session(), channel, result);
+	WebPageData::ApplyChanges(_session, channel, result);
 	for (auto i = _webPagesPending.begin(); i != _webPagesPending.cend();) {
 		if (i.value() == req) {
 			if (i.key()->pendingTill > 0) {
@@ -3103,7 +3106,7 @@ void ApiWrap::requestStickers(TimeId now) {
 		}
 	};
 	_stickersUpdateRequest = request(MTPmessages_GetAllStickers(
-		MTP_int(Api::CountStickersHash(&session(), true))
+		MTP_int(Api::CountStickersHash(_session, true))
 	)).done(onDone).fail([=](const RPCError &error) {
 		LOG(("App Fail: Failed to get stickers!"));
 		onDone(MTP_messages_allStickersNotModified());
@@ -3115,7 +3118,7 @@ void ApiWrap::requestRecentStickers(TimeId now) {
 		return;
 	}
 	requestRecentStickersWithHash(
-		Api::CountRecentStickersHash(&session()));
+		Api::CountRecentStickersHash(_session));
 }
 
 void ApiWrap::requestRecentStickersWithHash(int32 hash) {
@@ -3157,7 +3160,7 @@ void ApiWrap::requestFavedStickers(TimeId now) {
 		return;
 	}
 	_favedStickersUpdateRequest = request(MTPmessages_GetFavedStickers(
-		MTP_int(Api::CountFavedStickersHash(&session()))
+		MTP_int(Api::CountFavedStickersHash(_session))
 	)).done([=](const MTPmessages_FavedStickers &result) {
 		_session->data().stickers().setLastFavedUpdate(crl::now());
 		_favedStickersUpdateRequest = 0;
@@ -3189,7 +3192,7 @@ void ApiWrap::requestFeaturedStickers(TimeId now) {
 		return;
 	}
 	_featuredStickersUpdateRequest = request(MTPmessages_GetFeaturedStickers(
-		MTP_int(Api::CountFeaturedStickersHash(&session()))
+		MTP_int(Api::CountFeaturedStickersHash(_session))
 	)).done([=](const MTPmessages_FeaturedStickers &result) {
 		_session->data().stickers().setLastFeaturedUpdate(crl::now());
 		_featuredStickersUpdateRequest = 0;
@@ -3219,7 +3222,7 @@ void ApiWrap::requestSavedGifs(TimeId now) {
 		return;
 	}
 	_savedGifsUpdateRequest = request(MTPmessages_GetSavedGifs(
-		MTP_int(Api::CountSavedGifsHash(&session()))
+		MTP_int(Api::CountSavedGifsHash(_session))
 	)).done([=](const MTPmessages_SavedGifs &result) {
 		_session->data().stickers().setLastSavedGifsUpdate(crl::now());
 		_savedGifsUpdateRequest = 0;
@@ -3622,7 +3625,7 @@ void ApiWrap::requestSharedMedia(
 		return;
 	}
 
-	const auto history = session().data().history(peer);
+	const auto history = _session->data().history(peer);
 	auto &histories = history->owner().histories();
 	const auto requestType = Data::Histories::RequestType::History;
 	histories.sendRequest(history, requestType, [=](Fn<void()> finish) {
@@ -3988,18 +3991,35 @@ void ApiWrap::userPhotosDone(
 //}
 
 void ApiWrap::sendAction(const SendAction &action) {
-	session().data().histories().readInbox(action.history);
+	_session->data().histories().readInbox(action.history);
 	action.history->getReadyFor(ShowAtTheEndMsgId);
 	_sendActions.fire_copy(action);
 }
 
+void ApiWrap::finishForwarding(const SendAction &action) {
+	const auto history = action.history;
+	auto toForward = history->validateForwardDraft();
+	if (!toForward.empty()) {
+		const auto error = GetErrorTextForSending(history->peer, toForward);
+		if (!error.isEmpty()) {
+			return;
+		}
+
+		forwardMessages(std::move(toForward), action);
+		_session->data().cancelForwarding(history);
+	}
+
+	_session->data().sendHistoryChangeNotifications();
+	_session->data().newMessageSent(history);
+}
+
 void ApiWrap::forwardMessages(
 		HistoryItemsList &&items,
 		const SendAction &action,
 		FnMut<void()> &&successCallback) {
 	Expects(!items.empty());
 
-	auto &histories = session().data().histories();
+	auto &histories = _session->data().histories();
 
 	struct SharedCallback {
 		int requestsLeft = 0;
@@ -4094,7 +4114,7 @@ void ApiWrap::forwardMessages(
 			if (const auto message = item->toHistoryMessage()) {
 				const auto newId = FullMsgId(
 					peerToChannel(peer->id),
-					session().data().nextLocalMessageId());
+					_session->data().nextLocalMessageId());
 				const auto self = _session->user();
 				const auto messageFromId = channelPost
 					? UserId(0)
@@ -4170,7 +4190,7 @@ void ApiWrap::sendSharedContact(
 
 	const auto newId = FullMsgId(
 		history->channelId(),
-		session().data().nextLocalMessageId());
+		_session->data().nextLocalMessageId());
 	const auto channelPost = peer->isChannel() && !peer->isMegagroup();
 
 	auto flags = NewMessageFlags(peer) | MTPDmessage::Flag::f_media;
@@ -4227,11 +4247,8 @@ void ApiWrap::sendSharedContact(
 	options.silent = _session->data().notifySilentPosts(peer);
 	sendMedia(item, media, options);
 
-	if (const auto main = App::main()) {
-		_session->data().sendHistoryChangeNotifications();
-		main->historyToDown(history);
-		main->dialogsToUp();
-	}
+	_session->data().sendHistoryChangeNotifications();
+	_session->data().newMessageSent(history);
 }
 
 void ApiWrap::sendVoiceMessage(
@@ -4411,7 +4428,7 @@ void ApiWrap::editUploadedFile(
 	}
 
 	auto sentEntities = Api::EntitiesToMTP(
-		&session(),
+		_session,
 		item->originalText().entities,
 		Api::ConvertOption::SkipLocal);
 
@@ -4530,7 +4547,7 @@ void ApiWrap::sendMessage(MessageToSend &&message) {
 	while (TextUtilities::CutPart(sending, left, MaxMessageSize)) {
 		auto newId = FullMsgId(
 			peerToChannel(peer->id),
-			session().data().nextLocalMessageId());
+			_session->data().nextLocalMessageId());
 		auto randomId = rand_value<uint64>();
 
 		TextUtilities::Trim(sending);
@@ -4565,10 +4582,10 @@ void ApiWrap::sendMessage(MessageToSend &&message) {
 			sendFlags |= MTPmessages_SendMessage::Flag::f_silent;
 		}
 		auto localEntities = Api::EntitiesToMTP(
-			&session(),
+			_session,
 			sending.entities);
 		auto sentEntities = Api::EntitiesToMTP(
-			&session(),
+			_session,
 			sending.entities,
 			Api::ConvertOption::SkipLocal);
 		if (!sentEntities.v.isEmpty()) {
@@ -4640,9 +4657,7 @@ void ApiWrap::sendMessage(MessageToSend &&message) {
 		});
 	}
 
-	if (const auto main = App::main()) {
-		main->finishForwarding(action);
-	}
+	finishForwarding(action);
 }
 
 void ApiWrap::sendBotStart(not_null<UserData*> bot, PeerData *chat) {
@@ -4687,7 +4702,7 @@ void ApiWrap::sendInlineResult(
 	const auto peer = history->peer;
 	const auto newId = FullMsgId(
 		peerToChannel(peer->id),
-		session().data().nextLocalMessageId());
+		_session->data().nextLocalMessageId());
 	const auto randomId = rand_value<uint64>();
 
 	auto flags = NewMessageFlags(peer) | MTPDmessage::Flag::f_media;
@@ -4758,9 +4773,7 @@ void ApiWrap::sendInlineResult(
 		).send();
 		return history->sendRequestId;
 	});
-	if (const auto main = App::main()) {
-		main->finishForwarding(action);
-	}
+	finishForwarding(action);
 }
 
 void ApiWrap::uploadAlbumMedia(
@@ -4859,7 +4872,7 @@ void ApiWrap::sendMediaWithRandomId(
 	auto caption = item->originalText();
 	TextUtilities::Trim(caption);
 	auto sentEntities = Api::EntitiesToMTP(
-		&session(),
+		_session,
 		caption.entities,
 		Api::ConvertOption::SkipLocal);
 
@@ -5025,7 +5038,7 @@ void ApiWrap::uploadPeerPhoto(not_null<PeerData*> peer, QImage &&image) {
 
 	const auto fakeId = FullMsgId(
 		peerToChannel(peer->id),
-		session().data().nextLocalMessageId());
+		_session->data().nextLocalMessageId());
 	const auto already = ranges::find(
 		_peerPhotoUploads,
 		peer,
@@ -5536,7 +5549,7 @@ void ApiWrap::rescheduleMessage(
 		Api::SendOptions options) {
 	const auto text = item->originalText().text;
 	const auto sentEntities = Api::EntitiesToMTP(
-		&session(),
+		_session,
 		item->originalText().entities,
 		Api::ConvertOption::SkipLocal);
 	const auto media = item->media();
diff --git a/Telegram/SourceFiles/apiwrap.h b/Telegram/SourceFiles/apiwrap.h
index 1169fc198..f502f7f8d 100644
--- a/Telegram/SourceFiles/apiwrap.h
+++ b/Telegram/SourceFiles/apiwrap.h
@@ -374,6 +374,7 @@ public:
 		return _sendActions.events();
 	}
 	void sendAction(const SendAction &action);
+	void finishForwarding(const SendAction &action);
 	void forwardMessages(
 		HistoryItemsList &&items,
 		const SendAction &action,
diff --git a/Telegram/SourceFiles/app.cpp b/Telegram/SourceFiles/app.cpp
index cdc9e428f..018fefc2e 100644
--- a/Telegram/SourceFiles/app.cpp
+++ b/Telegram/SourceFiles/app.cpp
@@ -39,7 +39,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mainwidget.h"
 #include "apiwrap.h"
 #include "numbers.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "styles/style_boxes.h"
 #include "styles/style_overview.h"
diff --git a/Telegram/SourceFiles/boxes/add_contact_box.cpp b/Telegram/SourceFiles/boxes/add_contact_box.cpp
index c352047d5..8db083635 100644
--- a/Telegram/SourceFiles/boxes/add_contact_box.cpp
+++ b/Telegram/SourceFiles/boxes/add_contact_box.cpp
@@ -34,11 +34,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_chat.h"
 #include "data/data_user.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "data/data_cloud_file.h"
 #include "mainwidget.h"
 #include "mainwindow.h"
 #include "apiwrap.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "facades.h"
 #include "styles/style_layers.h"
@@ -817,11 +817,13 @@ void SetupChannelBox::prepare() {
 	connect(&_checkTimer, &QTimer::timeout, [=] { check(); });
 
 	_privacyGroup->setChangedCallback([this](Privacy value) { privacyChanged(value); });
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::InviteLinkChanged, [this](const Notify::PeerUpdate &update) {
-		if (update.peer == _channel) {
-			rtlupdate(_invitationLink);
-		}
-	}));
+
+	_channel->session().changes().peerUpdates(
+		_channel,
+		Data::PeerUpdate::Flag::InviteLink
+	) | rpl::start_with_next([=] {
+		rtlupdate(_invitationLink);
+	}, lifetime());
 
 	boxClosing() | rpl::start_with_next([=] {
 		if (!_existing) {
diff --git a/Telegram/SourceFiles/boxes/confirm_box.cpp b/Telegram/SourceFiles/boxes/confirm_box.cpp
index 61270a514..67f6872c3 100644
--- a/Telegram/SourceFiles/boxes/confirm_box.cpp
+++ b/Telegram/SourceFiles/boxes/confirm_box.cpp
@@ -33,9 +33,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_file_origin.h"
 #include "data/data_histories.h"
 #include "data/data_photo_media.h"
+#include "data/data_changes.h"
 #include "base/unixtime.h"
 #include "main/main_session.h"
-#include "observer_peer.h"
 #include "facades.h"
 #include "app.h"
 #include "styles/style_layers.h"
@@ -367,11 +367,12 @@ void MaxInviteBox::prepare() {
 	_textHeight = qMin(_text.countHeight(_textWidth), 16 * st::boxLabelStyle.lineHeight);
 	setDimensions(st::boxWidth, st::boxPadding.top() + _textHeight + st::boxTextFont->height + st::boxTextFont->height * 2 + st::newGroupLinkPadding.bottom());
 
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::InviteLinkChanged, [this](const Notify::PeerUpdate &update) {
-		if (update.peer == _channel) {
-			rtlupdate(_invitationLink);
-		}
-	}));
+	_channel->session().changes().peerUpdates(
+		_channel,
+		Data::PeerUpdate::Flag::InviteLink
+	) | rpl::start_with_next([=] {
+		rtlupdate(_invitationLink);
+	}, lifetime());
 }
 
 void MaxInviteBox::mouseMoveEvent(QMouseEvent *e) {
diff --git a/Telegram/SourceFiles/boxes/peer_list_box.cpp b/Telegram/SourceFiles/boxes/peer_list_box.cpp
index f99f27e62..a866b8a23 100644
--- a/Telegram/SourceFiles/boxes/peer_list_box.cpp
+++ b/Telegram/SourceFiles/boxes/peer_list_box.cpp
@@ -19,11 +19,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/wrap/slide_wrap.h"
 #include "ui/text_options.h"
 #include "lang/lang_keys.h"
-#include "observer_peer.h"
 #include "storage/file_download.h"
 #include "data/data_peer_values.h"
 #include "data/data_chat.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "base/unixtime.h"
 #include "window/themes/window_theme.h"
 #include "styles/style_layers.h"
@@ -666,15 +666,18 @@ PeerListContent::PeerListContent(
 		update();
 	});
 
-	using UpdateFlag = Notify::PeerUpdate::Flag;
-	auto changes = UpdateFlag::NameChanged | UpdateFlag::PhotoChanged;
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(changes, [this](const Notify::PeerUpdate &update) {
-		if (update.flags & UpdateFlag::PhotoChanged) {
-			this->update();
-		} else if (update.flags & UpdateFlag::NameChanged) {
-			handleNameChanged(update);
+	using UpdateFlag = Data::PeerUpdate::Flag;
+	_controller->session().changes().peerUpdates(
+		UpdateFlag::Name | UpdateFlag::Photo
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		if (update.flags & UpdateFlag::Name) {
+			handleNameChanged(update.peer);
 		}
-	}));
+		if (update.flags & UpdateFlag::Photo) {
+			this->update();
+		}
+	}, lifetime());
+
 	subscribe(Window::Theme::Background(), [this](const Window::Theme::BackgroundUpdate &update) {
 		if (update.paletteChanged()) {
 			invalidatePixmapsCache();
@@ -1717,8 +1720,8 @@ PeerListContent::RowIndex PeerListContent::findRowIndex(
 	return result;
 }
 
-void PeerListContent::handleNameChanged(const Notify::PeerUpdate &update) {
-	auto byPeer = _rowsByPeer.find(update.peer);
+void PeerListContent::handleNameChanged(not_null<PeerData*> peer) {
+	auto byPeer = _rowsByPeer.find(peer);
 	if (byPeer != _rowsByPeer.cend()) {
 		for (auto row : byPeer->second) {
 			if (addingToSearchIndex()) {
diff --git a/Telegram/SourceFiles/boxes/peer_list_box.h b/Telegram/SourceFiles/boxes/peer_list_box.h
index 8cb07163b..467299118 100644
--- a/Telegram/SourceFiles/boxes/peer_list_box.h
+++ b/Telegram/SourceFiles/boxes/peer_list_box.h
@@ -34,10 +34,6 @@ struct ScrollToRequest;
 class PopupMenu;
 } // namespace Ui
 
-namespace Notify {
-struct PeerUpdate;
-} // namespace Notify
-
 using PaintRoundImageCallback = Fn<void(
 	Painter &p,
 	int x,
@@ -551,7 +547,7 @@ protected:
 private:
 	void refreshIndices();
 	void removeRowAtIndex(std::vector<std::unique_ptr<PeerListRow>> &from, int index);
-	void handleNameChanged(const Notify::PeerUpdate &update);
+	void handleNameChanged(not_null<PeerData*> peer);
 
 	void invalidatePixmapsCache();
 
diff --git a/Telegram/SourceFiles/boxes/peer_list_controllers.cpp b/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
index d8e07c329..007da687a 100644
--- a/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
+++ b/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
@@ -8,7 +8,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/peer_list_controllers.h"
 
 #include "boxes/confirm_box.h"
-#include "observer_peer.h"
 #include "ui/widgets/checkbox.h"
 #include "ui/ui_utility.h"
 #include "main/main_session.h"
diff --git a/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp b/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
index 9cc8dcea5..fd2bd3ecc 100644
--- a/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
@@ -15,6 +15,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_user.h"
 #include "data/data_session.h"
 #include "data/data_folder.h"
+#include "data/data_changes.h"
 #include "history/history.h"
 #include "dialogs/dialogs_indexed_list.h"
 #include "base/unixtime.h"
@@ -23,7 +24,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mainwindow.h"
 #include "window/window_session_controller.h"
 #include "apiwrap.h"
-#include "observer_peer.h"
 #include "facades.h"
 #include "app.h"
 
@@ -348,17 +348,16 @@ void AddSpecialBoxController::prepareChatRows(not_null<ChatData*> chat) {
 		chat->updateFullForced();
 	}
 
-	using UpdateFlag = Notify::PeerUpdate::Flag;
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(
-		UpdateFlag::MembersChanged | UpdateFlag::AdminsChanged,
-		[=](const Notify::PeerUpdate &update) {
-			if (update.peer == chat) {
-				_additional.fillFromPeer();
-				if (update.flags & UpdateFlag::MembersChanged) {
-					rebuildChatRows(chat);
-				}
-			}
-		}));
+	using UpdateFlag = Data::PeerUpdate::Flag;
+	chat->session().changes().peerUpdates(
+		chat,
+		UpdateFlag::Members | UpdateFlag::Admins
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		_additional.fillFromPeer();
+		if (update.flags & UpdateFlag::Members) {
+			rebuildChatRows(chat);
+		}
+	}, lifetime());
 }
 
 void AddSpecialBoxController::rebuildChatRows(not_null<ChatData*> chat) {
diff --git a/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
index 80a27e8c2..43185f80d 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
@@ -16,13 +16,13 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "apiwrap.h"
 #include "lang/lang_keys.h"
 #include "mainwidget.h"
-#include "observer_peer.h"
 #include "dialogs/dialogs_indexed_list.h"
 #include "data/data_peer_values.h"
 #include "data/data_session.h"
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
+#include "data/data_changes.h"
 #include "base/unixtime.h"
 #include "ui/widgets/popup_menu.h"
 #include "ui/ui_utility.h"
@@ -286,20 +286,19 @@ void SubscribeToMigration(
 		if (const auto channel = peer->migrateTo()) {
 			migrate(channel);
 		} else if (!chat->isDeactivated()) {
-			const auto alive = lifetime.make_state<base::Subscription>();
-			const auto handler = [=](const Notify::PeerUpdate &update) {
-				if (update.peer == peer) {
-					if (const auto channel = peer->migrateTo()) {
-						const auto onstack = base::duplicate(migrate);
-						*alive = base::Subscription();
-						onstack(channel);
-					}
-				}
-			};
-			*alive = Notify::PeerUpdated().add_subscription(
-				Notify::PeerUpdatedHandler(
-					Notify::PeerUpdate::Flag::MigrationChanged,
-					handler));
+			chat->session().changes().peerUpdates(
+				peer,
+				Data::PeerUpdate::Flag::Migration
+			) | rpl::map([](const Data::PeerUpdate &update) {
+				return update.peer->migrateTo();
+			}) | rpl::filter([](ChannelData *channel) {
+				return (channel != nullptr);
+			}) | rpl::take(
+				1
+			) | rpl::start_with_next([=](not_null<ChannelData*> channel) {
+				const auto onstack = base::duplicate(migrate);
+				onstack(channel);
+			}, lifetime);
 		}
 	}
 }
@@ -686,17 +685,15 @@ ParticipantsOnlineSorter::ParticipantsOnlineSorter(
 : _peer(peer)
 , _delegate(delegate)
 , _sortByOnlineTimer([=] { sort(); }) {
-	const auto handleUpdate = [=](const Notify::PeerUpdate &update) {
+	peer->session().changes().peerUpdates(
+		Data::PeerUpdate::Flag::OnlineStatus
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
 		const auto peerId = update.peer->id;
 		if (const auto row = _delegate->peerListFindRow(peerId)) {
 			row->refreshStatus();
 			sortDelayed();
 		}
-	};
-
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(
-		Notify::PeerUpdate::Flag::UserOnlineChanged,
-		handleUpdate));
+	}, _lifetime);
 	sort();
 }
 
@@ -985,10 +982,10 @@ auto ParticipantsBoxController::saveState() const
 
 	const auto weak = result.get();
 	if (const auto chat = _peer->asChat()) {
-		Notify::PeerUpdateViewer(
+		chat->session().changes().peerUpdates(
 			chat,
-			Notify::PeerUpdate::Flag::MembersChanged
-		) | rpl::start_with_next([=](const Notify::PeerUpdate &) {
+			Data::PeerUpdate::Flag::Members
+		) | rpl::start_with_next([=] {
 			weak->controllerState = nullptr;
 		}, my->lifetime);
 	} else if (const auto channel = _peer->asMegagroup()) {
@@ -1104,23 +1101,20 @@ void ParticipantsBoxController::prepareChatRows(not_null<ChatData*> chat) {
 		chat->updateFullForced();
 	}
 
-	using UpdateFlag = Notify::PeerUpdate::Flag;
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(
-		UpdateFlag::MembersChanged
-		| UpdateFlag::AdminsChanged,
-		[=](const Notify::PeerUpdate &update) {
-			if (update.peer != chat) {
-				return;
-			}
-			_additional.fillFromPeer();
-			if ((update.flags & UpdateFlag::MembersChanged)
-				|| (_role == Role::Admins)) {
-				rebuildChatRows(chat);
-			}
-			if (update.flags & UpdateFlag::AdminsChanged) {
-				rebuildRowTypes();
-			}
-		}));
+	using UpdateFlag = Data::PeerUpdate::Flag;
+	chat->session().changes().peerUpdates(
+		chat,
+		UpdateFlag::Members | UpdateFlag::Admins
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		_additional.fillFromPeer();
+		if ((update.flags & UpdateFlag::Members)
+			|| (_role == Role::Admins)) {
+			rebuildChatRows(chat);
+		}
+		if (update.flags & UpdateFlag::Admins) {
+			rebuildRowTypes();
+		}
+	}, lifetime());
 }
 
 void ParticipantsBoxController::rebuildChatRows(not_null<ChatData*> chat) {
diff --git a/Telegram/SourceFiles/boxes/peers/edit_participants_box.h b/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
index 5c439f198..65d8994fa 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
+++ b/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
@@ -50,7 +50,7 @@ enum class ParticipantsRole {
 	Kicked,
 };
 
-class ParticipantsOnlineSorter : private base::Subscriber {
+class ParticipantsOnlineSorter {
 public:
 	ParticipantsOnlineSorter(
 		not_null<PeerData*> peer,
@@ -63,10 +63,11 @@ private:
 	void sortDelayed();
 	void refreshOnlineCount();
 
-	not_null<PeerData*> _peer;
-	not_null<PeerListDelegate*> _delegate;
+	const not_null<PeerData*> _peer;
+	const not_null<PeerListDelegate*> _delegate;
 	base::Timer _sortByOnlineTimer;
 	rpl::variable<int> _onlineCount = 0;
+	rpl::lifetime _lifetime;
 
 };
 
diff --git a/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
index 03ec4c4a3..a0a390fe3 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
@@ -29,7 +29,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mainwidget.h"
 #include "mainwindow.h"
 #include "mtproto/sender.h"
-#include "observer_peer.h"
 #include "ui/rp_widget.h"
 #include "ui/special_buttons.h"
 #include "ui/toast/toast.h"
diff --git a/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
index 5f2a891d8..4476fce8d 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
@@ -19,11 +19,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_chat.h"
 #include "data/data_peer.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "info/profile/info_profile_values.h"
 #include "lang/lang_keys.h"
 #include "mainwindow.h"
 #include "mtproto/sender.h"
-#include "observer_peer.h"
 #include "ui/rp_widget.h"
 #include "ui/special_buttons.h"
 #include "ui/toast/toast.h"
@@ -574,9 +574,9 @@ void Controller::observeInviteLink() {
 	if (!_controls.editInviteLinkWrap) {
 		return;
 	}
-	Notify::PeerUpdateValue(
+	_peer->session().changes().peerFlagsValue(
 		_peer,
-		Notify::PeerUpdate::Flag::InviteLinkChanged
+		Data::PeerUpdate::Flag::InviteLink
 	) | rpl::start_with_next([=] {
 		refreshCreateInviteLink();
 		refreshEditInviteLink();
diff --git a/Telegram/SourceFiles/boxes/share_box.cpp b/Telegram/SourceFiles/boxes/share_box.cpp
index a2a223be9..3f333a498 100644
--- a/Telegram/SourceFiles/boxes/share_box.cpp
+++ b/Telegram/SourceFiles/boxes/share_box.cpp
@@ -8,7 +8,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/share_box.h"
 
 #include "dialogs/dialogs_indexed_list.h"
-#include "observer_peer.h"
 #include "lang/lang_keys.h"
 #include "mainwindow.h"
 #include "mainwidget.h"
@@ -35,6 +34,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_user.h"
 #include "data/data_session.h"
 #include "data/data_folder.h"
+#include "data/data_changes.h"
 #include "main/main_session.h"
 #include "core/application.h"
 #include "styles/style_layers.h"
@@ -91,7 +91,6 @@ private:
 		Ui::Animations::Simple nameActive;
 	};
 
-	void notifyPeerUpdated(const Notify::PeerUpdate &update);
 	void invalidateCache();
 
 	int displayedChatsCount() const;
@@ -558,11 +557,19 @@ ShareBox::Inner::Inner(
 	_filter = qsl("a");
 	updateFilter();
 
-	using UpdateFlag = Notify::PeerUpdate::Flag;
-	auto observeEvents = UpdateFlag::NameChanged | UpdateFlag::PhotoChanged;
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(observeEvents, [this](const Notify::PeerUpdate &update) {
-		notifyPeerUpdated(update);
-	}));
+	_navigation->session().changes().peerUpdates(
+		Data::PeerUpdate::Flag::Photo
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		updateChat(update.peer);
+	}, lifetime());
+
+	_navigation->session().changes().realtimeNameUpdates(
+	) | rpl::start_with_next([=](const Data::NameUpdate &update) {
+		_chatsIndexed->peerNameChanged(
+			update.peer,
+			update.oldFirstLetters);
+	}, lifetime());
+
 	subscribe(_navigation->session().downloaderTaskFinished(), [=] {
 		update();
 	});
@@ -616,16 +623,6 @@ void ShareBox::Inner::activateSkipPage(int pageHeight, int direction) {
 	activateSkipRow(direction * (pageHeight / _rowHeight));
 }
 
-void ShareBox::Inner::notifyPeerUpdated(const Notify::PeerUpdate &update) {
-	if (update.flags & Notify::PeerUpdate::Flag::NameChanged) {
-		_chatsIndexed->peerNameChanged(
-			update.peer,
-			update.oldNameFirstLetters);
-	}
-
-	updateChat(update.peer);
-}
-
 void ShareBox::Inner::updateChat(not_null<PeerData*> peer) {
 	if (const auto i = _dataMap.find(peer); i != end(_dataMap)) {
 		updateChatName(i->second.get(), peer);
diff --git a/Telegram/SourceFiles/boxes/share_box.h b/Telegram/SourceFiles/boxes/share_box.h
index 14a0e0dbc..605b68f63 100644
--- a/Telegram/SourceFiles/boxes/share_box.h
+++ b/Telegram/SourceFiles/boxes/share_box.h
@@ -33,10 +33,6 @@ class Row;
 class IndexedList;
 } // namespace Dialogs
 
-namespace Notify {
-struct PeerUpdate;
-} // namespace Notify
-
 namespace Ui {
 class MultiSelect;
 class InputField;
diff --git a/Telegram/SourceFiles/calls/calls_box_controller.cpp b/Telegram/SourceFiles/calls/calls_box_controller.cpp
index 88754cb92..3f7dd8c38 100644
--- a/Telegram/SourceFiles/calls/calls_box_controller.cpp
+++ b/Telegram/SourceFiles/calls/calls_box_controller.cpp
@@ -10,7 +10,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "styles/style_calls.h"
 #include "styles/style_boxes.h"
 #include "lang/lang_keys.h"
-#include "observer_peer.h"
 #include "ui/effects/ripple_animation.h"
 #include "calls/calls_instance.h"
 #include "history/history.h"
diff --git a/Telegram/SourceFiles/calls/calls_panel.cpp b/Telegram/SourceFiles/calls/calls_panel.cpp
index 43c7b3486..abf7c9ec7 100644
--- a/Telegram/SourceFiles/calls/calls_panel.cpp
+++ b/Telegram/SourceFiles/calls/calls_panel.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_file_origin.h"
 #include "data/data_photo_media.h"
 #include "data/data_cloud_file.h"
+#include "data/data_changes.h"
 #include "calls/calls_emoji_fingerprint.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
@@ -28,7 +29,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "lang/lang_keys.h"
 #include "main/main_session.h"
 #include "apiwrap.h"
-#include "observer_peer.h"
 #include "platform/platform_specific.h"
 #include "window/main_window.h"
 #include "layout.h"
@@ -361,13 +361,7 @@ void Panel::initControls() {
 	subscribe(_call->muteChanged(), [this](bool mute) {
 		_mute->setIconOverride(mute ? &st::callUnmuteIcon : nullptr);
 	});
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::NameChanged, [this](const Notify::PeerUpdate &update) {
-		if (!_call || update.peer != _call->user()) {
-			return;
-		}
-		_name->setText(_call->user()->name);
-		updateControlsGeometry();
-	}));
+
 	_updateDurationTimer.setCallback([this] {
 		if (_call) {
 			updateStatusText(_call->state());
@@ -423,7 +417,7 @@ void Panel::reinitControls() {
 		st::callPanelSignalBars,
 		[=] { rtlupdate(signalBarsRect()); });
 
-	_name->setText(_call->user()->name);
+	_name->setText(_user->name);
 	updateStatusText(_call->state());
 }
 
@@ -435,12 +429,22 @@ void Panel::initLayout() {
 
 	initGeometry();
 
-	Notify::PeerUpdateValue(
-		_user,
-		Notify::PeerUpdate::Flag::PhotoChanged
-	) | rpl::start_with_next(
-		[this] { processUserPhoto(); },
-		lifetime());
+	using UpdateFlag = Data::PeerUpdate::Flag;
+	_user->session().changes().peerUpdates(
+		UpdateFlag::Name | UpdateFlag::Photo
+	) | rpl::filter([=](const Data::PeerUpdate &update) {
+		// _user may change for the same Panel.
+		return (_call != nullptr) && (update.peer == _user);
+	}) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		if (update.flags & UpdateFlag::Name) {
+			_name->setText(_call->user()->name);
+			updateControlsGeometry();
+		}
+		if (update.flags & UpdateFlag::Photo) {
+			processUserPhoto();
+		}
+	}, lifetime());
+	processUserPhoto();
 
 	subscribe(_user->session().downloaderTaskFinished(), [=] {
 		refreshUserPhoto();
diff --git a/Telegram/SourceFiles/calls/calls_top_bar.cpp b/Telegram/SourceFiles/calls/calls_top_bar.cpp
index f4e0d76aa..1eb33b46e 100644
--- a/Telegram/SourceFiles/calls/calls_top_bar.cpp
+++ b/Telegram/SourceFiles/calls/calls_top_bar.cpp
@@ -15,8 +15,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "calls/calls_instance.h"
 #include "calls/calls_panel.h"
 #include "data/data_user.h"
+#include "data/data_changes.h"
 #include "main/main_session.h"
-#include "observer_peer.h"
 #include "boxes/abstract_box.h"
 #include "base/timer.h"
 #include "layout.h"
@@ -101,13 +101,16 @@ void TopBar::initControls() {
 		setMuted(mute);
 		update();
 	});
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::NameChanged, [this](const Notify::PeerUpdate &update) {
-		if (auto call = _call.get()) {
-			if (update.peer == call->user()) {
-				updateInfoLabels();
-			}
-		}
-	}));
+
+	_call->user()->session().changes().peerUpdates(
+		Data::PeerUpdate::Flag::Name
+	) | rpl::filter([=](const Data::PeerUpdate &update) {
+		// _user may change for the same Panel.
+		return (_call != nullptr) && (update.peer == _call->user());
+	}) | rpl::start_with_next([=] {
+		updateInfoLabels();
+	}, lifetime());
+
 	setInfoLabels();
 	_info->setClickedCallback([=] {
 		if (const auto call = _call.get()) {
diff --git a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
index 4de94aaa1..ea87276a8 100644
--- a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
+++ b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "data/data_file_origin.h"
 #include "data/data_cloud_file.h"
+#include "data/data_changes.h"
 #include "chat_helpers/stickers_lottie.h"
 #include "ui/widgets/buttons.h"
 #include "ui/effects/animations.h"
@@ -32,7 +33,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/confirm_box.h"
 #include "window/window_session_controller.h" // GifPauseReason.
 #include "main/main_session.h"
-#include "observer_peer.h"
 #include "apiwrap.h"
 #include "app.h"
 #include "styles/style_chat_helpers.h"
@@ -896,11 +896,19 @@ StickersListWidget::StickersListWidget(
 			readVisibleFeatured(getVisibleTop(), getVisibleBottom());
 		}
 	});
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::ChannelStickersChanged, [this](const Notify::PeerUpdate &update) {
-		if (update.peer == _megagroupSet) {
-			refreshStickers();
-		}
-	}));
+
+	session().changes().peerUpdates(
+		Data::PeerUpdate::Flag::StickersSet
+	) | rpl::filter([=](const Data::PeerUpdate &update) {
+		return (update.peer.get() == _megagroupSet);
+	}) | rpl::start_with_next([=] {
+		refreshStickers();
+	}, lifetime());
+
+	session().data().stickers().recentUpdated(
+	) | rpl::start_with_next([=] {
+		refreshRecent();
+	}, lifetime());
 }
 
 Main::Session &StickersListWidget::session() const {
diff --git a/Telegram/SourceFiles/chat_helpers/tabbed_selector.cpp b/Telegram/SourceFiles/chat_helpers/tabbed_selector.cpp
index 3185964a4..075bca788 100644
--- a/Telegram/SourceFiles/chat_helpers/tabbed_selector.cpp
+++ b/Telegram/SourceFiles/chat_helpers/tabbed_selector.cpp
@@ -20,10 +20,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/localstorage.h"
 #include "data/data_channel.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "data/stickers/data_stickers.h"
 #include "lang/lang_keys.h"
 #include "mainwindow.h"
-#include "observer_peer.h"
 #include "apiwrap.h"
 #include "styles/style_chat_helpers.h"
 
@@ -347,16 +347,13 @@ TabbedSelector::TabbedSelector(
 	if (full()) {
 		_tabsSlider->raise();
 
-		const auto handleUpdate = [=](const Notify::PeerUpdate &update) {
-			if (update.peer == _currentPeer) {
-				checkRestrictedPeer();
-			}
-		};
-		subscribe(
-			Notify::PeerUpdated(),
-			Notify::PeerUpdatedHandler(
-				Notify::PeerUpdate::Flag::RightsChanged,
-				handleUpdate));
+		session().changes().peerUpdates(
+			Data::PeerUpdate::Flag::Rights
+		) | rpl::filter([=](const Data::PeerUpdate &update) {
+			return (update.peer.get() == _currentPeer);
+		}) | rpl::start_with_next([=] {
+			checkRestrictedPeer();
+		}, lifetime());
 
 		session().api().stickerSetInstalled(
 		) | rpl::start_with_next([this](uint64 setId) {
diff --git a/Telegram/SourceFiles/core/application.cpp b/Telegram/SourceFiles/core/application.cpp
index 8d1864451..e02935f4e 100644
--- a/Telegram/SourceFiles/core/application.cpp
+++ b/Telegram/SourceFiles/core/application.cpp
@@ -35,7 +35,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "lang/lang_translator.h"
 #include "lang/lang_cloud_manager.h"
 #include "lang/lang_hardcoded.h"
-#include "observer_peer.h"
 #include "storage/storage_databases.h"
 #include "mainwidget.h"
 #include "core/file_utilities.h"
@@ -502,10 +501,6 @@ void Application::call_handleUnreadCounterUpdate() {
 	Global::RefUnreadCounterUpdate().notify(true);
 }
 
-void Application::call_handleDelayedPeerUpdates() {
-	Notify::peerUpdatedSendDelayed();
-}
-
 void Application::call_handleObservables() {
 	base::HandleObservables();
 }
diff --git a/Telegram/SourceFiles/core/application.h b/Telegram/SourceFiles/core/application.h
index edf6d8739..498f5f278 100644
--- a/Telegram/SourceFiles/core/application.h
+++ b/Telegram/SourceFiles/core/application.h
@@ -229,7 +229,6 @@ public:
 	void writeInstallBetaVersionsSetting();
 
 	void call_handleUnreadCounterUpdate();
-	void call_handleDelayedPeerUpdates();
 	void call_handleObservables();
 
 protected:
diff --git a/Telegram/SourceFiles/data/data_changes.cpp b/Telegram/SourceFiles/data/data_changes.cpp
new file mode 100644
index 000000000..461d97e3e
--- /dev/null
+++ b/Telegram/SourceFiles/data/data_changes.cpp
@@ -0,0 +1,169 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "data/data_changes.h"
+
+#include "main/main_session.h"
+
+namespace Data {
+
+template <typename DataType, typename UpdateType>
+void Changes::Manager<DataType, UpdateType>::updated(
+		not_null<DataType*> data,
+		Flags flags) {
+	sendRealtimeNotifications(data, flags);
+}
+
+template <typename DataType, typename UpdateType>
+void Changes::Manager<DataType, UpdateType>::sendRealtimeNotifications(
+		not_null<DataType*> data,
+		Flags flags) {
+	auto clearRealtime = false;
+	for (auto i = 0; i != kCount; ++i) {
+		const auto flag = static_cast<Flag>(1U << i);
+		if (flags & flag) {
+			_realtimeStreams[i].fire({ data, flags });
+		}
+	}
+}
+
+template <typename DataType, typename UpdateType>
+rpl::producer<UpdateType> Changes::Manager<DataType, UpdateType>::updates(
+		Flags flags) const {
+	return _stream.events(
+	) | rpl::filter([=](const UpdateType &update) {
+		return (update.flags & flags);
+	});
+}
+
+template <typename DataType, typename UpdateType>
+rpl::producer<UpdateType> Changes::Manager<DataType, UpdateType>::updates(
+		not_null<DataType*> data,
+		Flags flags) const {
+	return _stream.events(
+	) | rpl::filter([=](const UpdateType &update) {
+		const auto [updateData, updateFlags] = update;
+		return (updateData == data) && (updateFlags & flags);
+	});
+}
+
+template <typename DataType, typename UpdateType>
+auto Changes::Manager<DataType, UpdateType>::realtimeUpdates(Flag flag) const
+-> rpl::producer<UpdateType> {
+	return _realtimeStreams[CountBit(flag)].events();
+}
+
+template <typename DataType, typename UpdateType>
+rpl::producer<UpdateType> Changes::Manager<DataType, UpdateType>::flagsValue(
+		not_null<DataType*> data,
+		Flags flags) const {
+	return rpl::single(
+		UpdateType{ data, flags }
+	) | rpl::then(updates(data, flags));
+}
+
+template <typename DataType, typename UpdateType>
+void Changes::Manager<DataType, UpdateType>::sendNotifications() {
+	for (const auto [data, flags] : base::take(_updates)) {
+		_stream.fire({ data, flags });
+	}
+}
+
+Changes::Changes(not_null<Main::Session*> session) : _session(session) {
+}
+
+Main::Session &Changes::session() const {
+	return *_session;
+}
+
+void Changes::nameUpdated(
+		not_null<PeerData*> peer,
+		base::flat_set<QChar> oldFirstLetters) {
+	_nameStream.fire({ peer, std::move(oldFirstLetters) });
+}
+
+rpl::producer<NameUpdate> Changes::realtimeNameUpdates() const {
+	return _nameStream.events();
+}
+
+rpl::producer<NameUpdate> Changes::realtimeNameUpdates(
+		not_null<PeerData*> peer) const {
+	return _nameStream.events() | rpl::filter([=](const NameUpdate &update) {
+		return (update.peer == peer);
+	});
+}
+
+void Changes::peerUpdated(not_null<PeerData*> peer, PeerUpdate::Flags flags) {
+	_peerChanges.updated(peer, flags);
+	scheduleNotifications();
+}
+
+rpl::producer<PeerUpdate> Changes::peerUpdates(
+		PeerUpdate::Flags flags) const {
+	return _peerChanges.updates(flags);
+}
+
+rpl::producer<PeerUpdate> Changes::peerUpdates(
+		not_null<PeerData*> peer,
+		PeerUpdate::Flags flags) const {
+	return _peerChanges.updates(peer, flags);
+}
+
+rpl::producer<PeerUpdate> Changes::peerFlagsValue(
+		not_null<PeerData*> peer,
+		PeerUpdate::Flags flags) const {
+	return _peerChanges.flagsValue(peer, flags);
+}
+
+rpl::producer<PeerUpdate> Changes::realtimePeerUpdates(
+		PeerUpdate::Flag flag) const {
+	return _peerChanges.realtimeUpdates(flag);
+}
+
+void Changes::historyUpdated(
+		not_null<History*> history,
+		HistoryUpdate::Flags flags) {
+	_historyChanges.updated(history, flags);
+	scheduleNotifications();
+}
+
+rpl::producer<HistoryUpdate> Changes::historyUpdates(
+		HistoryUpdate::Flags flags) const {
+	return _historyChanges.updates(flags);
+}
+
+rpl::producer<HistoryUpdate> Changes::historyUpdates(
+		not_null<History*> history,
+		HistoryUpdate::Flags flags) const {
+	return _historyChanges.updates(history, flags);
+}
+
+rpl::producer<HistoryUpdate> Changes::historyFlagsValue(
+		not_null<History*> history,
+		HistoryUpdate::Flags flags) const {
+	return _historyChanges.flagsValue(history, flags);
+}
+
+void Changes::scheduleNotifications() {
+	if (!_notify) {
+		_notify = true;
+		crl::on_main(&session(), [=] {
+			sendNotifications();
+		});
+	}
+}
+
+void Changes::sendNotifications() {
+	if (!_notify) {
+		return;
+	}
+	_notify = false;
+	_peerChanges.sendNotifications();
+	_historyChanges.sendNotifications();
+}
+
+} // namespace Data
diff --git a/Telegram/SourceFiles/data/data_changes.h b/Telegram/SourceFiles/data/data_changes.h
new file mode 100644
index 000000000..6c84c4949
--- /dev/null
+++ b/Telegram/SourceFiles/data/data_changes.h
@@ -0,0 +1,197 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "base/flags.h"
+
+class History;
+class PeerData;
+
+namespace Data {
+
+struct NameUpdate {
+	NameUpdate(
+		not_null<PeerData*> peer,
+		base::flat_set<QChar> oldFirstLetters)
+	: peer(peer)
+	, oldFirstLetters(std::move(oldFirstLetters)) {
+	}
+
+	not_null<PeerData*> peer;
+	base::flat_set<QChar> oldFirstLetters;
+};
+
+struct PeerUpdate {
+	enum class Flag : uint32 {
+		None = 0,
+
+		// Common flags
+		Name              = (1 << 0),
+		Username          = (1 << 1),
+		Photo             = (1 << 2),
+		About             = (1 << 3),
+		Notifications     = (1 << 4),
+		Migration         = (1 << 5),
+		UnavailableReason = (1 << 6),
+		PinnedMessage     = (1 << 7),
+
+		// For users
+		CanShareContact   = (1 << 8),
+		IsContact         = (1 << 9),
+		PhoneNumber       = (1 << 10),
+		IsBlocked         = (1 << 11),
+		OnlineStatus      = (1 << 12),
+		BotCommands       = (1 << 13),
+		BotCanBeInvited   = (1 << 14),
+		CommonChats       = (1 << 15),
+		HasCalls          = (1 << 16),
+		SupportInfo       = (1 << 17),
+		IsBot             = (1 << 18),
+
+		// For chats and channels
+		InviteLink        = (1 << 19),
+		Members           = (1 << 20),
+		Admins            = (1 << 21),
+		BannedUsers       = (1 << 22),
+		Rights            = (1 << 23),
+
+		// For channels
+		ChannelAmIn       = (1 << 24),
+		StickersSet       = (1 << 25),
+		ChannelLinkedChat = (1 << 26),
+		ChannelLocation   = (1 << 27),
+		Slowmode          = (1 << 28),
+
+		// For iteration
+		LastUsedBit       = (1 << 28),
+	};
+	using Flags = base::flags<Flag>;
+	friend inline constexpr auto is_flag_type(Flag) { return true; }
+
+	not_null<PeerData*> peer;
+	Flags flags = 0;
+
+};
+
+struct HistoryUpdate {
+	enum class Flag : uint32 {
+		None = 0,
+
+		IsPinned       = (1 << 0),
+		UnreadView     = (1 << 1),
+		TopPromoted    = (1 << 2),
+		Folder         = (1 << 3),
+		UnreadMentions = (1 << 4),
+		LocalMessages  = (1 << 5),
+		ChatOccupied   = (1 << 6),
+
+		LastUsedBit    = (1 << 6),
+	};
+	using Flags = base::flags<Flag>;
+	friend inline constexpr auto is_flag_type(Flag) { return true; }
+
+	not_null<History*> history;
+	Flags flags = 0;
+
+};
+
+class Changes final {
+public:
+	explicit Changes(not_null<Main::Session*> session);
+
+	[[nodiscard]] Main::Session &session() const;
+
+	void nameUpdated(
+		not_null<PeerData*> peer,
+		base::flat_set<QChar> oldFirstLetters);
+	[[nodiscard]] rpl::producer<NameUpdate> realtimeNameUpdates() const;
+	[[nodiscard]] rpl::producer<NameUpdate> realtimeNameUpdates(
+		not_null<PeerData*> peer) const;
+
+	void peerUpdated(not_null<PeerData*> peer, PeerUpdate::Flags flags);
+	[[nodiscard]] rpl::producer<PeerUpdate> peerUpdates(
+		PeerUpdate::Flags flags) const;
+	[[nodiscard]] rpl::producer<PeerUpdate> peerUpdates(
+		not_null<PeerData*> peer,
+		PeerUpdate::Flags flags) const;
+	[[nodiscard]] rpl::producer<PeerUpdate> peerFlagsValue(
+		not_null<PeerData*> peer,
+		PeerUpdate::Flags flags) const;
+	[[nodiscard]] rpl::producer<PeerUpdate> realtimePeerUpdates(
+		PeerUpdate::Flag flag) const;
+
+	void historyUpdated(
+		not_null<History*> history,
+		HistoryUpdate::Flags flags);
+	[[nodiscard]] rpl::producer<HistoryUpdate> historyUpdates(
+		HistoryUpdate::Flags flags) const;
+	[[nodiscard]] rpl::producer<HistoryUpdate> historyUpdates(
+		not_null<History*> history,
+		HistoryUpdate::Flags flags) const;
+	[[nodiscard]] rpl::producer<HistoryUpdate> historyFlagsValue(
+		not_null<History*> history,
+		HistoryUpdate::Flags flags) const;
+
+	void sendNotifications();
+
+private:
+	template <typename Flag>
+	static constexpr int CountBit(Flag Last = Flag::LastUsedBit) {
+		auto i = 0;
+		while ((1ULL << i) != static_cast<uint64>(Last)) {
+			++i;
+			Assert(i != 64);
+		}
+		return (i + 1);
+	}
+
+	template <typename DataType, typename UpdateType>
+	class Manager final {
+	public:
+		using Flag = typename UpdateType::Flag;
+		using Flags = typename UpdateType::Flags;
+
+		void updated(not_null<DataType*> data, Flags flags);
+		[[nodiscard]] rpl::producer<UpdateType> updates(Flags flags) const;
+		[[nodiscard]] rpl::producer<UpdateType> updates(
+			not_null<DataType*> data,
+			Flags flags) const;
+		[[nodiscard]] rpl::producer<UpdateType> flagsValue(
+			not_null<DataType*> data,
+			Flags flags) const;
+		[[nodiscard]] rpl::producer<UpdateType> realtimeUpdates(
+			Flag flag) const;
+
+		void sendNotifications();
+
+	private:
+		static constexpr auto kCount = CountBit<Flag>();
+
+		void sendRealtimeNotifications(not_null<DataType*> data, Flags flags);
+
+		std::array<rpl::event_stream<UpdateType>, kCount> _realtimeStreams;
+		base::flat_map<not_null<DataType*>, Flags> _updates;
+		rpl::event_stream<UpdateType> _stream;
+
+	};
+
+	static constexpr auto kHistoryCount = CountBit<HistoryUpdate::Flag>();
+
+	void scheduleNotifications();
+
+	const not_null<Main::Session*> _session;
+
+	rpl::event_stream<NameUpdate> _nameStream;
+	Manager<PeerData, PeerUpdate> _peerChanges;
+	Manager<History, HistoryUpdate> _historyChanges;
+
+	bool _notify = false;
+
+};
+
+} // namespace Data
diff --git a/Telegram/SourceFiles/data/data_channel.cpp b/Telegram/SourceFiles/data/data_channel.cpp
index 1d3746f7a..0feaa3887 100644
--- a/Telegram/SourceFiles/data/data_channel.cpp
+++ b/Telegram/SourceFiles/data/data_channel.cpp
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 
 #include "data/data_peer_values.h"
+#include "data/data_changes.h"
 #include "data/data_channel_admins.h"
 #include "data/data_user.h"
 #include "data/data_chat.h"
@@ -17,13 +18,12 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_histories.h"
 #include "base/unixtime.h"
 #include "history/history.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "apiwrap.h"
 
 namespace {
 
-using UpdateFlag = Notify::PeerUpdate::Flag;
+using UpdateFlag = Data::PeerUpdate::Flag;
 
 } // namespace
 
@@ -66,8 +66,8 @@ ChannelData::ChannelData(not_null<Data::Session*> owner, PeerId id)
 	) | rpl::distinct_until_changed(
 	) | rpl::start_with_next([=] {
 		if (const auto chat = getMigrateFromChat()) {
-			Notify::peerUpdatedDelayed(chat, UpdateFlag::MigrationChanged);
-			Notify::peerUpdatedDelayed(this, UpdateFlag::MigrationChanged);
+			session().changes().peerUpdated(chat, UpdateFlag::Migration);
+			session().changes().peerUpdated(this, UpdateFlag::Migration);
 		}
 	}, _lifetime);
 }
@@ -97,7 +97,7 @@ void ChannelData::setAccessHash(uint64 accessHash) {
 void ChannelData::setInviteLink(const QString &newInviteLink) {
 	if (newInviteLink != _inviteLink) {
 		_inviteLink = newInviteLink;
-		Notify::peerUpdatedDelayed(this, UpdateFlag::InviteLinkChanged);
+		session().changes().peerUpdated(this, UpdateFlag::InviteLink);
 	}
 }
 
@@ -131,9 +131,9 @@ void ChannelData::setLocation(const MTPChannelLocation &data) {
 	const auto now = mgInfo->getLocation();
 	const auto nowValue = now ? *now : ChannelLocation();
 	if (was != now || (was && wasValue != nowValue)) {
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			this,
-			Notify::PeerUpdate::Flag::ChannelLocation);
+			UpdateFlag::ChannelLocation);
 	}
 }
 
@@ -144,7 +144,7 @@ const ChannelLocation *ChannelData::getLocation() const {
 void ChannelData::setLinkedChat(ChannelData *linked) {
 	if (_linkedChat != linked) {
 		_linkedChat = linked;
-		Notify::peerUpdatedDelayed(this, UpdateFlag::ChannelLinkedChat);
+		session().changes().peerUpdated(this, UpdateFlag::ChannelLinkedChat);
 	}
 }
 
@@ -159,28 +159,28 @@ void ChannelData::setMembersCount(int newMembersCount) {
 			mgInfo->lastParticipantsCount = membersCount();
 		}
 		_membersCount = newMembersCount;
-		Notify::peerUpdatedDelayed(this, Notify::PeerUpdate::Flag::MembersChanged);
+		session().changes().peerUpdated(this, UpdateFlag::Members);
 	}
 }
 
 void ChannelData::setAdminsCount(int newAdminsCount) {
 	if (_adminsCount != newAdminsCount) {
 		_adminsCount = newAdminsCount;
-		Notify::peerUpdatedDelayed(this, Notify::PeerUpdate::Flag::AdminsChanged);
+		session().changes().peerUpdated(this, UpdateFlag::Admins);
 	}
 }
 
 void ChannelData::setRestrictedCount(int newRestrictedCount) {
 	if (_restrictedCount != newRestrictedCount) {
 		_restrictedCount = newRestrictedCount;
-		Notify::peerUpdatedDelayed(this, Notify::PeerUpdate::Flag::BannedUsersChanged);
+		session().changes().peerUpdated(this, UpdateFlag::BannedUsers);
 	}
 }
 
 void ChannelData::setKickedCount(int newKickedCount) {
 	if (_kickedCount != newKickedCount) {
 		_kickedCount = newKickedCount;
-		Notify::peerUpdatedDelayed(this, Notify::PeerUpdate::Flag::BannedUsersChanged);
+		session().changes().peerUpdated(this, UpdateFlag::BannedUsers);
 	}
 }
 
@@ -260,13 +260,11 @@ void ChannelData::applyEditAdmin(
 		setAdminsCount(adminsCount() + 1);
 		updateFullForced();
 	}
-	Notify::peerUpdatedDelayed(
-		this,
-		Notify::PeerUpdate::Flag::AdminsChanged);
+	session().changes().peerUpdated(this, UpdateFlag::Admins);
 }
 
 void ChannelData::applyEditBanned(not_null<UserData*> user, const MTPChatBannedRights &oldRights, const MTPChatBannedRights &newRights) {
-	auto flags = Notify::PeerUpdate::Flag::BannedUsersChanged | Notify::PeerUpdate::Flag::None;
+	auto flags = UpdateFlag::BannedUsers | UpdateFlag::None;
 	auto isKicked = (newRights.c_chatBannedRights().vflags().v & MTPDchatBannedRights::Flag::f_view_messages);
 	auto isRestricted = !isKicked && (newRights.c_chatBannedRights().vflags().v != 0);
 	if (mgInfo) {
@@ -276,7 +274,7 @@ void ChannelData::applyEditBanned(not_null<UserData*> user, const MTPChatBannedR
 			if (adminsCount() > 1) {
 				setAdminsCount(adminsCount() - 1);
 			} else {
-				flags |= Notify::PeerUpdate::Flag::AdminsChanged;
+				flags |= UpdateFlag::Admins;
 			}
 		}
 		auto it = mgInfo->lastRestricted.find(user);
@@ -312,7 +310,7 @@ void ChannelData::applyEditBanned(not_null<UserData*> user, const MTPChatBannedR
 						mgInfo->botStatus = -1;
 					}
 				}
-				flags |= Notify::PeerUpdate::Flag::MembersChanged;
+				flags |= UpdateFlag::Members;
 				owner().removeMegagroupParticipant(this, user);
 			}
 		}
@@ -321,12 +319,12 @@ void ChannelData::applyEditBanned(not_null<UserData*> user, const MTPChatBannedR
 		if (isKicked) {
 			if (membersCount() > 1) {
 				setMembersCount(membersCount() - 1);
-				flags |= Notify::PeerUpdate::Flag::MembersChanged;
+				flags |= UpdateFlag::Members;
 			}
 			setKickedCount(kickedCount() + 1);
 		}
 	}
-	Notify::peerUpdatedDelayed(this, flags);
+	session().changes().peerUpdated(this, flags);
 }
 
 void ChannelData::markForbidden() {
@@ -366,12 +364,11 @@ auto ChannelData::unavailableReasons() const
 	return _unavailableReasons;
 }
 
-void ChannelData::setUnavailableReasons(std::vector<Data::UnavailableReason> &&reasons) {
+void ChannelData::setUnavailableReasons(
+		std::vector<Data::UnavailableReason> &&reasons) {
 	if (_unavailableReasons != reasons) {
 		_unavailableReasons = std::move(reasons);
-		Notify::peerUpdatedDelayed(
-			this,
-			Notify::PeerUpdate::Flag::UnavailableReasonChanged);
+		session().changes().peerUpdated(this, UpdateFlag::UnavailableReason);
 	}
 }
 
@@ -538,7 +535,9 @@ void ChannelData::setAdminRights(const MTPChatAdminRights &rights) {
 			mgInfo->lastAdmins.remove(self);
 		}
 	}
-	Notify::peerUpdatedDelayed(this, UpdateFlag::RightsChanged | UpdateFlag::AdminsChanged | UpdateFlag::BannedUsersChanged);
+	session().changes().peerUpdated(
+		this,
+		UpdateFlag::Rights | UpdateFlag::Admins | UpdateFlag::BannedUsers);
 }
 
 void ChannelData::setRestrictions(const MTPChatBannedRights &rights) {
@@ -561,7 +560,9 @@ void ChannelData::setRestrictions(const MTPChatBannedRights &rights) {
 			mgInfo->lastRestricted.remove(self);
 		}
 	}
-	Notify::peerUpdatedDelayed(this, UpdateFlag::RightsChanged | UpdateFlag::AdminsChanged | UpdateFlag::BannedUsersChanged);
+	session().changes().peerUpdated(
+		this,
+		UpdateFlag::Rights | UpdateFlag::Admins | UpdateFlag::BannedUsers);
 }
 
 void ChannelData::setDefaultRestrictions(const MTPChatBannedRights &rights) {
@@ -569,7 +570,7 @@ void ChannelData::setDefaultRestrictions(const MTPChatBannedRights &rights) {
 		return;
 	}
 	_defaultRestrictions.set(rights.c_chatBannedRights().vflags().v);
-	Notify::peerUpdatedDelayed(this, UpdateFlag::RightsChanged);
+	session().changes().peerUpdated(this, UpdateFlag::Rights);
 }
 
 auto ChannelData::applyUpdateVersion(int version) -> UpdateStatus {
@@ -597,7 +598,7 @@ void ChannelData::setMigrateFromChat(ChatData *chat) {
 	if (chat != info->getMigrateFromChat()) {
 		info->setMigrateFromChat(chat);
 		if (amIn()) {
-			Notify::peerUpdatedDelayed(this, UpdateFlag::MigrationChanged);
+			session().changes().peerUpdated(this, UpdateFlag::Migration);
 		}
 	}
 }
@@ -611,7 +612,7 @@ void ChannelData::setSlowmodeSeconds(int seconds) {
 		return;
 	}
 	_slowmodeSeconds = seconds;
-	Notify::peerUpdatedDelayed(this, UpdateFlag::ChannelSlowmode);
+	session().changes().peerUpdated(this, UpdateFlag::Slowmode);
 }
 
 TimeId ChannelData::slowmodeLastMessage() const {
@@ -628,7 +629,7 @@ void ChannelData::growSlowmodeLastMessage(TimeId when) {
 	} else {
 		_slowmodeLastMessage = when;
 	}
-	Notify::peerUpdatedDelayed(this, UpdateFlag::ChannelSlowmode);
+	session().changes().peerUpdated(this, UpdateFlag::Slowmode);
 }
 
 namespace Data {
@@ -655,6 +656,8 @@ void ApplyChannelUpdate(
 void ApplyChannelUpdate(
 		not_null<ChannelData*> channel,
 		const MTPDchannelFull &update) {
+	const auto session = &channel->session();
+
 	channel->setAvailableMinId(update.vavailable_min_id().value_or_empty());
 	auto canViewAdmins = channel->canViewAdmins();
 	auto canViewMembers = channel->canViewMembers();
@@ -672,7 +675,7 @@ void ApplyChannelUpdate(
 		item.match([&](const MTPDbotInfo &info) {
 			if (const auto user = owner.userLoaded(info.vuser_id().v)) {
 				user->setBotInfo(item);
-				channel->session().api().fullPeerUpdated().notify(user);
+				session->api().fullPeerUpdated().notify(user);
 			}
 		});
 	}
@@ -746,21 +749,17 @@ void ApplyChannelUpdate(
 				: MTP_inputStickerSetEmpty();
 		}
 		if (stickersChanged) {
-			Notify::peerUpdatedDelayed(
-				channel,
-				Notify::PeerUpdate::Flag::ChannelStickersChanged);
+			session->changes().peerUpdated(channel, UpdateFlag::StickersSet);
 		}
 	}
 	channel->fullUpdated();
 
 	if (canViewAdmins != channel->canViewAdmins()
 		|| canViewMembers != channel->canViewMembers()) {
-		Notify::peerUpdatedDelayed(
-			channel,
-			Notify::PeerUpdate::Flag::RightsChanged);
+		session->changes().peerUpdated(channel, UpdateFlag::Rights);
 	}
 
-	channel->session().api().applyNotifySettings(
+	session->api().applyNotifySettings(
 		MTP_inputNotifyPeer(channel->input),
 		update.vnotify_settings());
 
diff --git a/Telegram/SourceFiles/data/data_chat.cpp b/Telegram/SourceFiles/data/data_chat.cpp
index d3dfbc9e9..502cb2595 100644
--- a/Telegram/SourceFiles/data/data_chat.cpp
+++ b/Telegram/SourceFiles/data/data_chat.cpp
@@ -10,14 +10,14 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_user.h"
 #include "data/data_channel.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "history/history.h"
 #include "main/main_session.h"
 #include "apiwrap.h"
-#include "observer_peer.h"
 
 namespace {
 
-using UpdateFlag = Notify::PeerUpdate::Flag;
+using UpdateFlag = Data::PeerUpdate::Flag;
 
 } // namespace
 
@@ -96,16 +96,12 @@ void ChatData::setName(const QString &newName) {
 }
 
 void ChatData::applyEditAdmin(not_null<UserData*> user, bool isAdmin) {
-	auto flags = Notify::PeerUpdate::Flag::AdminsChanged
-		| Notify::PeerUpdate::Flag::None;
 	if (isAdmin) {
 		admins.emplace(user);
 	} else {
 		admins.remove(user);
 	}
-	Notify::peerUpdatedDelayed(
-		this,
-		Notify::PeerUpdate::Flag::AdminsChanged);
+	session().changes().peerUpdated(this, UpdateFlag::Admins);
 }
 
 void ChatData::invalidateParticipants() {
@@ -115,15 +111,15 @@ void ChatData::invalidateParticipants() {
 	//setDefaultRestrictions(MTP_chatBannedRights(MTP_flags(0), MTP_int(0)));
 	invitedByMe.clear();
 	botStatus = 0;
-	Notify::peerUpdatedDelayed(
+	session().changes().peerUpdated(
 		this,
-		UpdateFlag::MembersChanged | UpdateFlag::AdminsChanged);
+		UpdateFlag::Members | UpdateFlag::Admins);
 }
 
 void ChatData::setInviteLink(const QString &newInviteLink) {
 	if (newInviteLink != _inviteLink) {
 		_inviteLink = newInviteLink;
-		Notify::peerUpdatedDelayed(this, UpdateFlag::InviteLinkChanged);
+		session().changes().peerUpdated(this, UpdateFlag::InviteLink);
 	}
 }
 
@@ -132,11 +128,9 @@ void ChatData::setAdminRights(const MTPChatAdminRights &rights) {
 		return;
 	}
 	_adminRights.set(rights.c_chatAdminRights().vflags().v);
-	Notify::peerUpdatedDelayed(
+	session().changes().peerUpdated(
 		this,
-		(UpdateFlag::RightsChanged
-			| UpdateFlag::AdminsChanged
-			| UpdateFlag::BannedUsersChanged));
+		UpdateFlag::Rights | UpdateFlag::Admins | UpdateFlag::BannedUsers);
 }
 
 void ChatData::setDefaultRestrictions(const MTPChatBannedRights &rights) {
@@ -144,7 +138,7 @@ void ChatData::setDefaultRestrictions(const MTPChatBannedRights &rights) {
 		return;
 	}
 	_defaultRestrictions.set(rights.c_chatBannedRights().vflags().v);
-	Notify::peerUpdatedDelayed(this, UpdateFlag::RightsChanged);
+	session().changes().peerUpdated(this, UpdateFlag::Rights);
 }
 
 void ChatData::refreshBotStatus() {
@@ -176,7 +170,7 @@ void ChatData::setMigrateToChannel(ChannelData *channel) {
 	if (_migratedTo != channel) {
 		_migratedTo = channel;
 		if (channel->amIn()) {
-			Notify::peerUpdatedDelayed(this, UpdateFlag::MigrationChanged);
+			session().changes().peerUpdated(this, UpdateFlag::Migration);
 		}
 	}
 }
@@ -199,6 +193,7 @@ void ApplyChatUpdate(
 		return;
 	}
 	const auto user = chat->owner().userLoaded(update.vuser_id().v);
+	const auto session = &chat->session();
 	if (!user
 		|| (!chat->participants.empty()
 			&& chat->participants.contains(user))) {
@@ -213,7 +208,7 @@ void ApplyChatUpdate(
 		chat->botStatus = 0;
 	} else {
 		chat->participants.emplace(user);
-		if (update.vinviter_id().v == chat->session().userId()) {
+		if (update.vinviter_id().v == session->userId()) {
 			chat->invitedByMe.insert(user);
 		} else {
 			chat->invitedByMe.remove(user);
@@ -222,13 +217,11 @@ void ApplyChatUpdate(
 		if (user->isBot()) {
 			chat->botStatus = 2;
 			if (!user->botInfo->inited) {
-				chat->session().api().requestFullPeer(user);
+				session->api().requestFullPeer(user);
 			}
 		}
 	}
-	Notify::peerUpdatedDelayed(
-		chat,
-		Notify::PeerUpdate::Flag::MembersChanged);
+	session->changes().peerUpdated(chat, UpdateFlag::Members);
 }
 
 void ApplyChatUpdate(
@@ -270,9 +263,7 @@ void ApplyChatUpdate(
 			chat->refreshBotStatus();
 		}
 	}
-	Notify::peerUpdatedDelayed(
-		chat,
-		Notify::PeerUpdate::Flag::MembersChanged);
+	chat->session().changes().peerUpdated(chat, UpdateFlag::Members);
 }
 
 void ApplyChatUpdate(
@@ -282,7 +273,7 @@ void ApplyChatUpdate(
 		!= ChatData::UpdateStatus::Good) {
 		return;
 	}
-
+	const auto session = &chat->session();
 	const auto user = chat->owner().userLoaded(update.vuser_id().v);
 	if (!user) {
 		chat->invalidateParticipants();
@@ -295,16 +286,14 @@ void ApplyChatUpdate(
 	}
 	if (mtpIsTrue(update.vis_admin())) {
 		if (chat->noParticipantInfo()) {
-			chat->session().api().requestFullPeer(chat);
+			session->api().requestFullPeer(chat);
 		} else {
 			chat->admins.emplace(user);
 		}
 	} else {
 		chat->admins.erase(user);
 	}
-	Notify::peerUpdatedDelayed(
-		chat,
-		Notify::PeerUpdate::Flag::AdminsChanged);
+	session->changes().peerUpdated(chat, UpdateFlag::Admins);
 }
 
 void ApplyChatUpdate(
@@ -360,6 +349,7 @@ void ApplyChatUpdate(not_null<ChatData*> chat, const MTPDchatFull &update) {
 void ApplyChatUpdate(
 		not_null<ChatData*> chat,
 		const MTPChatParticipants &participants) {
+	const auto session = &chat->session();
 	participants.match([&](const MTPDchatParticipantsForbidden &data) {
 		if (const auto self = data.vself_participant()) {
 			// self->
@@ -381,7 +371,7 @@ void ApplyChatUpdate(
 		chat->invitedByMe.clear();
 		chat->admins.clear();
 		chat->setAdminRights(MTP_chatAdminRights(MTP_flags(0)));
-		const auto selfUserId = chat->session().userId();
+		const auto selfUserId = session->userId();
 		for (const auto &participant : list) {
 			const auto userId = participant.match([&](const auto &data) {
 				return data.vuser_id().v;
@@ -430,10 +420,9 @@ void ApplyChatUpdate(
 			}
 		}
 		chat->refreshBotStatus();
-		Notify::peerUpdatedDelayed(
+		session->changes().peerUpdated(
 			chat,
-			Notify::PeerUpdate::Flag::MembersChanged
-			| Notify::PeerUpdate::Flag::AdminsChanged);
+			UpdateFlag::Members | UpdateFlag::Admins);
 	});
 }
 
diff --git a/Telegram/SourceFiles/data/data_chat_filters.cpp b/Telegram/SourceFiles/data/data_chat_filters.cpp
index de643c064..7234f6401 100644
--- a/Telegram/SourceFiles/data/data_chat_filters.cpp
+++ b/Telegram/SourceFiles/data/data_chat_filters.cpp
@@ -236,6 +236,7 @@ not_null<Dialogs::MainList*> ChatFilters::chatsList(FilterId filterId) {
 	auto &pointer = _chatsLists[filterId];
 	if (!pointer) {
 		pointer = std::make_unique<Dialogs::MainList>(
+			&_owner->session(),
 			filterId,
 			rpl::single(ChatFilter::kPinnedLimit));
 	}
diff --git a/Telegram/SourceFiles/data/data_folder.cpp b/Telegram/SourceFiles/data/data_folder.cpp
index 9d461258f..a28f68d3d 100644
--- a/Telegram/SourceFiles/data/data_folder.cpp
+++ b/Telegram/SourceFiles/data/data_folder.cpp
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_session.h"
 #include "data/data_channel.h"
 #include "data/data_histories.h"
+#include "data/data_changes.h"
 #include "dialogs/dialogs_key.h"
 #include "history/history.h"
 #include "history/history_item.h"
@@ -19,7 +20,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "main/main_account.h"
 //#include "storage/storage_feed_messages.h" // #feed
 #include "main/main_session.h"
-#include "observer_peer.h"
 #include "apiwrap.h"
 #include "mainwidget.h"
 #include "facades.h"
@@ -57,20 +57,20 @@ rpl::producer<int> PinnedDialogsInFolderMaxValue(
 Folder::Folder(not_null<Data::Session*> owner, FolderId id)
 : Entry(owner, this)
 , _id(id)
-, _chatsList(FilterId(), PinnedDialogsInFolderMaxValue(&owner->session()))
+, _chatsList(
+	&owner->session(),
+	FilterId(),
+	PinnedDialogsInFolderMaxValue(&owner->session()))
 , _name(tr::lng_archived_name(tr::now)) {
 	indexNameParts();
 
-	Notify::PeerUpdateViewer(
-		Notify::PeerUpdate::Flag::NameChanged
-	) | rpl::start_with_next([=](const Notify::PeerUpdate &update) {
-		for (const auto history : _lastHistories) {
-			if (history->peer == update.peer) {
-				++_chatListViewVersion;
-				updateChatListEntryPostponed();
-				return;
-			}
-		}
+	session().changes().peerUpdates(
+		PeerUpdate::Flag::Name
+	) | rpl::filter([=](const PeerUpdate &update) {
+		return ranges::contains(_lastHistories, update.peer, &History::peer);
+	}) | rpl::start_with_next([=] {
+		++_chatListViewVersion;
+		updateChatListEntryPostponed();
 	}, _lifetime);
 
 	_chatsList.setAllAreMuted(true);
diff --git a/Telegram/SourceFiles/data/data_peer.cpp b/Telegram/SourceFiles/data/data_peer.cpp
index e9f195d8b..4b1aadc1c 100644
--- a/Telegram/SourceFiles/data/data_peer.cpp
+++ b/Telegram/SourceFiles/data/data_peer.cpp
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_user.h"
 #include "data/data_chat.h"
 #include "data/data_channel.h"
+#include "data/data_changes.h"
 #include "data/data_photo.h"
 #include "data/data_folder.h"
 #include "data/data_session.h"
@@ -18,7 +19,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/unixtime.h"
 #include "base/crc32hash.h"
 #include "lang/lang_keys.h"
-#include "observer_peer.h"
 #include "apiwrap.h"
 #include "boxes/confirm_box.h"
 #include "main/main_session.h"
@@ -42,7 +42,7 @@ namespace {
 constexpr auto kUpdateFullPeerTimeout = crl::time(5000); // Not more than once in 5 seconds.
 constexpr auto kUserpicSize = 160;
 
-using UpdateFlag = Notify::PeerUpdate::Flag;
+using UpdateFlag = Data::PeerUpdate::Flag;
 
 } // namespace
 
@@ -147,15 +147,17 @@ void PeerData::updateNameDelayed(
 	_nameText.setText(st::msgNameStyle, name, Ui::NameTextOptions());
 	_userpicEmpty = nullptr;
 
-	Notify::PeerUpdate update(this);
-	if (nameVersion++ > 1) {
-		update.flags |= UpdateFlag::NameChanged;
-		update.oldNameFirstLetters = nameFirstLetters();
+	auto flags = UpdateFlag::None | UpdateFlag::None;
+	auto oldFirstLetters = base::flat_set<QChar>();
+	const auto nameUpdated = (nameVersion++ > 1);
+	if (nameUpdated) {
+		oldFirstLetters = nameFirstLetters();
+		flags |= UpdateFlag::Name;
 	}
 	if (isUser()) {
 		if (asUser()->username != newUsername) {
 			asUser()->username = newUsername;
-			update.flags |= UpdateFlag::UsernameChanged;
+			flags |= UpdateFlag::Username;
 		}
 		asUser()->setNameOrPhone(newNameOrPhone);
 	} else if (isChannel()) {
@@ -167,12 +169,15 @@ void PeerData::updateNameDelayed(
 			} else {
 				asChannel()->addFlags(MTPDchannel::Flag::f_username);
 			}
-			update.flags |= UpdateFlag::UsernameChanged;
+			flags |= UpdateFlag::Username;
 		}
 	}
 	fillNames();
-	if (update.flags) {
-		Notify::PeerUpdated().notify(update, true);
+	if (nameUpdated) {
+		session().changes().nameUpdated(this, std::move(oldFirstLetters));
+	}
+	if (flags) {
+		session().changes().peerUpdated(this, flags);
 	}
 }
 
@@ -204,7 +209,7 @@ void PeerData::setUserpicPhoto(const MTPPhoto &data) {
 	});
 	if (_userpicPhotoId != photoId) {
 		_userpicPhotoId = photoId;
-		Notify::peerUpdatedDelayed(this, UpdateFlag::PhotoChanged);
+		session().changes().peerUpdated(this, UpdateFlag::Photo);
 	}
 }
 
@@ -384,7 +389,7 @@ void PeerData::setUserpicChecked(
 		const ImageLocation &location) {
 	if (_userpicPhotoId != photoId || _userpic.location() != location) {
 		setUserpic(photoId, location);
-		Notify::peerUpdatedDelayed(this, UpdateFlag::PhotoChanged);
+		session().changes().peerUpdated(this, UpdateFlag::Photo);
 		//if (const auto channel = asChannel()) { // #feed
 		//	if (const auto feed = channel->feed()) {
 		//		owner().notifyFeedUpdated(
@@ -454,9 +459,7 @@ void PeerData::setPinnedMessageId(MsgId messageId) {
 	messageId = (messageId > min) ? messageId : MsgId(0);
 	if (_pinnedMessageId != messageId) {
 		_pinnedMessageId = messageId;
-		Notify::peerUpdatedDelayed(
-			this,
-			Notify::PeerUpdate::Flag::PinnedMessageChanged);
+		session().changes().peerUpdated(this, UpdateFlag::PinnedMessage);
 	}
 }
 
@@ -479,7 +482,7 @@ bool PeerData::setAbout(const QString &newAbout) {
 		return false;
 	}
 	_about = newAbout;
-	Notify::peerUpdatedDelayed(this, UpdateFlag::AboutChanged);
+	session().changes().peerUpdated(this, UpdateFlag::About);
 	return true;
 }
 
diff --git a/Telegram/SourceFiles/data/data_session.cpp b/Telegram/SourceFiles/data/data_session.cpp
index b7de383de..7e3e20cd4 100644
--- a/Telegram/SourceFiles/data/data_session.cpp
+++ b/Telegram/SourceFiles/data/data_session.cpp
@@ -7,7 +7,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "data/data_session.h"
 
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "apiwrap.h"
 #include "mainwidget.h"
@@ -34,6 +33,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "window/themes/window_theme.h"
 #include "lang/lang_keys.h" // tr::lng_deleted(tr::now) in user name
 #include "data/stickers/data_stickers.h"
+#include "data/data_changes.h"
 #include "data/data_media_types.h"
 #include "data/data_folder.h"
 #include "data/data_channel.h"
@@ -209,7 +209,7 @@ Session::Session(not_null<Main::Session*> session)
 , _bigFileCache(Core::App().databases().get(
 	_session->local().cacheBigFilePath(),
 	_session->local().cacheBigFileSettings()))
-, _chatsList(FilterId(), PinnedDialogsCountMaxValue(session))
+, _chatsList(session, FilterId(), PinnedDialogsCountMaxValue(session))
 , _contactsList(Dialogs::SortMode::Name)
 , _contactsNoChatsList(Dialogs::SortMode::Name)
 , _selfDestructTimer([=] { checkSelfDestructItems(); })
@@ -353,8 +353,8 @@ not_null<UserData*> Session::processUser(const MTPUser &data) {
 	const MTPUserStatus *status = nullptr;
 	const MTPUserStatus emptyStatus = MTP_userStatusEmpty();
 
-	Notify::PeerUpdate update;
-	using UpdateFlag = Notify::PeerUpdate::Flag;
+	using UpdateFlag = PeerUpdate::Flag;
+	auto flags = UpdateFlag::None | UpdateFlag::None;
 	data.match([&](const MTPDuserEmpty &data) {
 		const auto canShareThisContact = result->canShareThisContactFast();
 
@@ -366,13 +366,13 @@ not_null<UserData*> Session::processUser(const MTPUser &data) {
 		result->setFlags(MTPDuser::Flag::f_deleted);
 		if (!result->phone().isEmpty()) {
 			result->setPhone(QString());
-			update.flags |= UpdateFlag::UserPhoneChanged;
+			flags |= UpdateFlag::PhoneNumber;
 		}
 		result->setBotInfoVersion(-1);
 		status = &emptyStatus;
 		result->setIsContact(false);
 		if (canShareThisContact != result->canShareThisContactFast()) {
-			update.flags |= UpdateFlag::UserCanShareContact;
+			flags |= UpdateFlag::CanShareContact;
 		}
 	}, [&](const MTPDuser &data) {
 		minimal = data.is_min();
@@ -405,7 +405,7 @@ not_null<UserData*> Session::processUser(const MTPUser &data) {
 		if (data.is_deleted()) {
 			if (!result->phone().isEmpty()) {
 				result->setPhone(QString());
-				update.flags |= UpdateFlag::UserPhoneChanged;
+				flags |= UpdateFlag::PhoneNumber;
 			}
 			result->setName(tr::lng_deleted(tr::now), QString(), QString(), QString());
 			result->setPhoto(MTP_userProfilePhotoEmpty());
@@ -423,7 +423,7 @@ not_null<UserData*> Session::processUser(const MTPUser &data) {
 			const auto phoneChanged = (result->phone() != phone);
 			if (phoneChanged) {
 				result->setPhone(phone);
-				update.flags |= UpdateFlag::UserPhoneChanged;
+				flags |= UpdateFlag::PhoneNumber;
 			}
 			const auto nameChanged = (result->firstName != fname)
 				|| (result->lastName != lname);
@@ -475,7 +475,7 @@ not_null<UserData*> Session::processUser(const MTPUser &data) {
 				result->botInfo->readsAllHistory = data.is_bot_chat_history();
 				if (result->botInfo->cantJoinGroups != data.is_bot_nochats()) {
 					result->botInfo->cantJoinGroups = data.is_bot_nochats();
-					update.flags |= UpdateFlag::BotCanAddToGroups;
+					flags |= UpdateFlag::BotCanBeInvited;
 				}
 				if (const auto placeholder = data.vbot_inline_placeholder()) {
 					result->botInfo->inlinePlaceholder = '_' + qs(*placeholder);
@@ -490,7 +490,7 @@ not_null<UserData*> Session::processUser(const MTPUser &data) {
 		}
 
 		if (canShareThisContact != result->canShareThisContactFast()) {
-			update.flags |= UpdateFlag::UserCanShareContact;
+			flags |= UpdateFlag::CanShareContact;
 		}
 	});
 
@@ -510,15 +510,12 @@ not_null<UserData*> Session::processUser(const MTPUser &data) {
 			oldOnlineTill);
 		if (oldOnlineTill != newOnlineTill) {
 			result->onlineTill = newOnlineTill;
-			update.flags |= UpdateFlag::UserOnlineChanged;
+			flags |= UpdateFlag::OnlineStatus;
 		}
 	}
 
-	if (App::main()) {
-		if (update.flags) {
-			update.peer = result;
-			Notify::peerUpdatedDelayed(update);
-		}
+	if (flags) {
+		session().changes().peerUpdated(result, flags);
 	}
 	return result;
 }
@@ -537,9 +534,8 @@ not_null<PeerData*> Session::processChat(const MTPChat &data) {
 	});
 	auto minimal = false;
 
-	Notify::PeerUpdate update;
-	using UpdateFlag = Notify::PeerUpdate::Flag;
-
+	using UpdateFlag = Data::PeerUpdate::Flag;
+	auto flags = UpdateFlag::None | UpdateFlag::None;
 	data.match([&](const MTPDchat &data) {
 		const auto chat = result->asChat();
 
@@ -585,7 +581,7 @@ not_null<PeerData*> Session::processChat(const MTPChat &data) {
 		chat->count = data.vparticipants_count().v;
 
 		if (canAddMembers != chat->canAddMembers()) {
-			update.flags |= UpdateFlag::RightsChanged;
+			flags |= UpdateFlag::Rights;
 		}
 	}, [&](const MTPDchatForbidden &data) {
 		const auto chat = result->asChat();
@@ -604,7 +600,7 @@ not_null<PeerData*> Session::processChat(const MTPChat &data) {
 			MTP_chatBannedRights(MTP_flags(0), MTP_int(0)));
 
 		if (canAddMembers != chat->canAddMembers()) {
-			update.flags |= UpdateFlag::RightsChanged;
+			flags |= UpdateFlag::Rights;
 		}
 	}, [&](const MTPDchannel &data) {
 		const auto channel = result->asChannel();
@@ -676,12 +672,12 @@ not_null<PeerData*> Session::processChat(const MTPChat &data) {
 		channel->setPhoto(data.vphoto());
 
 		if (wasInChannel != channel->amIn()) {
-			update.flags |= UpdateFlag::ChannelAmIn;
+			flags |= UpdateFlag::ChannelAmIn;
 		}
 		if (canViewAdmins != channel->canViewAdmins()
 			|| canViewMembers != channel->canViewMembers()
 			|| canAddMembers != channel->canAddMembers()) {
-			update.flags |= UpdateFlag::RightsChanged;
+			flags |= UpdateFlag::Rights;
 		}
 	}, [&](const MTPDchannelForbidden &data) {
 		const auto channel = result->asChannel();
@@ -709,12 +705,12 @@ not_null<PeerData*> Session::processChat(const MTPChat &data) {
 		channel->setMembersCount(0);
 
 		if (wasInChannel != channel->amIn()) {
-			update.flags |= UpdateFlag::ChannelAmIn;
+			flags |= UpdateFlag::ChannelAmIn;
 		}
 		if (canViewAdmins != channel->canViewAdmins()
 			|| canViewMembers != channel->canViewMembers()
 			|| canAddMembers != channel->canAddMembers()) {
-			update.flags |= UpdateFlag::RightsChanged;
+			flags |= UpdateFlag::Rights;
 		}
 	}, [](const MTPDchatEmpty &) {
 	});
@@ -726,9 +722,8 @@ not_null<PeerData*> Session::processChat(const MTPChat &data) {
 	} else if (result->loadedStatus != PeerData::FullLoaded) {
 		result->loadedStatus = PeerData::FullLoaded;
 	}
-	if (update.flags) {
-		update.peer = result;
-		Notify::peerUpdatedDelayed(update);
+	if (flags) {
+		session().changes().peerUpdated(result, flags);
 	}
 	return result;
 }
@@ -841,6 +836,22 @@ void Session::deleteConversationLocally(not_null<PeerData*> peer) {
 		}
 	}
 }
+void Session::newMessageSent(not_null<History*> history) {
+	_newMessageSent.fire_copy(history);
+}
+
+rpl::producer<not_null<History*>> Session::newMessageSent() const {
+	return _newMessageSent.events();
+}
+
+void Session::cancelForwarding(not_null<History*> history) {
+	history->setForwardDraft({});
+	_forwardDraftUpdated.fire_copy(history);
+}
+
+rpl::producer<not_null<History*>> Session::forwardDraftUpdates() const {
+	return _forwardDraftUpdated.events();
+}
 
 void Session::registerSendAction(
 		not_null<History*> history,
@@ -1034,25 +1045,27 @@ void Session::forgetPassportCredentials() {
 }
 
 void Session::setupContactViewsViewer() {
-	Notify::PeerUpdateViewer(
-		Notify::PeerUpdate::Flag::UserIsContact
-	) | rpl::map([](const Notify::PeerUpdate &update) {
+	session().changes().peerUpdates(
+		PeerUpdate::Flag::IsContact
+	) | rpl::map([](const PeerUpdate &update) {
 		return update.peer->asUser();
-	}) | rpl::filter([](UserData *user) {
-		return user != nullptr;
 	}) | rpl::start_with_next([=](not_null<UserData*> user) {
-		userIsContactUpdated(user);
+		const auto i = _contactViews.find(peerToUser(user->id));
+		if (i != _contactViews.end()) {
+			for (const auto view : i->second) {
+				requestViewResize(view);
+			}
+		}
 	}, _lifetime);
 }
 
 void Session::setupChannelLeavingViewer() {
-	Notify::PeerUpdateViewer(
-		Notify::PeerUpdate::Flag::ChannelAmIn
-	) | rpl::map([](const Notify::PeerUpdate &update) {
+	session().changes().peerUpdates(
+		PeerUpdate::Flag::ChannelAmIn
+	) | rpl::map([](const PeerUpdate &update) {
 		return update.peer->asChannel();
-	}) | rpl::filter([](ChannelData *channel) {
-		return (channel != nullptr)
-			&& !(channel->amIn());
+	}) | rpl::filter([](not_null<ChannelData*> channel) {
+		return !(channel->amIn());
 	}) | rpl::start_with_next([=](not_null<ChannelData*> channel) {
 //		channel->clearFeed(); // #feed
 		if (const auto history = historyLoaded(channel->id)) {
@@ -1064,23 +1077,21 @@ void Session::setupChannelLeavingViewer() {
 }
 
 void Session::setupPeerNameViewer() {
-	Notify::PeerUpdateViewer(
-		Notify::PeerUpdate::Flag::NameChanged
-	) | rpl::start_with_next([=](const Notify::PeerUpdate &update) {
+	session().changes().realtimeNameUpdates(
+	) | rpl::start_with_next([=](const NameUpdate &update) {
 		const auto peer = update.peer;
-		const auto &oldLetters = update.oldNameFirstLetters;
+		const auto &oldLetters = update.oldFirstLetters;
 		_contactsNoChatsList.peerNameChanged(peer, oldLetters);
 		_contactsList.peerNameChanged(peer, oldLetters);
 	}, _lifetime);
 }
 
 void Session::setupUserIsContactViewer() {
-	Notify::PeerUpdateViewer(
-		Notify::PeerUpdate::Flag::UserIsContact
-	) | rpl::filter([=](const Notify::PeerUpdate &update) {
-		return update.peer->isUser();
-	}) | rpl::start_with_next([=](const Notify::PeerUpdate &update) {
+	session().changes().peerUpdates(
+		PeerUpdate::Flag::IsContact
+	) | rpl::start_with_next([=](const PeerUpdate &update) {
 		const auto user = update.peer->asUser();
+		Assert(user != nullptr);
 		if (user->loadedStatus != PeerData::FullLoaded) {
 			LOG(("API Error: "
 				"userIsContactChanged() called for a not loaded user!"));
@@ -1505,15 +1516,6 @@ rpl::producer<not_null<UserData*>> Session::megagroupParticipantAdded(
 	});
 }
 
-void Session::userIsContactUpdated(not_null<UserData*> user) {
-	const auto i = _contactViews.find(peerToUser(user->id));
-	if (i != _contactViews.end()) {
-		for (const auto view : i->second) {
-			requestViewResize(view);
-		}
-	}
-}
-
 HistoryItemsList Session::idsToItems(
 		const MessageIdsList &ids) const {
 	return ranges::view::all(
@@ -1972,9 +1974,9 @@ void Session::updateNotifySettingsLocal(not_null<PeerData*> peer) {
 	if (history && history->changeMute(muted)) {
 		// Notification already sent.
 	} else {
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			peer,
-			Notify::PeerUpdate::Flag::NotificationsEnabled);
+			PeerUpdate::Flag::Notifications);
 	}
 
 	if (muted) {
@@ -3157,9 +3159,9 @@ void Session::registerContactItem(
 	_contactItems[contactId].insert(item);
 
 	if (contact && canShare != contact->canShareThisContact()) {
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			contact,
-			Notify::PeerUpdate::Flag::UserCanShareContact);
+			PeerUpdate::Flag::CanShareContact);
 	}
 
 	if (const auto i = _views.find(item); i != _views.end()) {
@@ -3189,9 +3191,9 @@ void Session::unregisterContactItem(
 	}
 
 	if (contact && canShare != contact->canShareThisContact()) {
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			contact,
-			Notify::PeerUpdate::Flag::UserCanShareContact);
+			PeerUpdate::Flag::CanShareContact);
 	}
 }
 
@@ -3739,36 +3741,33 @@ MessageIdsList Session::takeMimeForwardIds() {
 }
 
 void Session::setTopPromoted(
-		PeerData *promoted,
+		History *promoted,
 		const QString &type,
 		const QString &message) {
 	const auto changed = (_topPromoted != promoted);
-	const auto history = promoted ? this->history(promoted).get() : nullptr;
-	if (changed
-		|| (history && history->topPromotionMessage() != message)) {
-		if (changed) {
-			if (const auto history = historyLoaded(_topPromoted)) {
-				history->cacheTopPromotion(false, QString(), QString());
-			}
-		}
-		const auto old = std::exchange(_topPromoted, promoted);
-		if (history) {
-			history->cacheTopPromotion(true, type, message);
-			history->requestChatListMessage();
-			Notify::peerUpdatedDelayed(
-				_topPromoted,
-				Notify::PeerUpdate::Flag::TopPromotedChanged);
-		}
-		if (changed && old) {
-			Notify::peerUpdatedDelayed(
-				old,
-				Notify::PeerUpdate::Flag::TopPromotedChanged);
+	if (!changed
+		&& (!promoted || promoted->topPromotionMessage() == message)) {
+		return;
+	}
+	if (changed) {
+		if (_topPromoted) {
+			_topPromoted->cacheTopPromotion(false, QString(), QString());
 		}
 	}
-}
-
-PeerData *Session::topPromoted() const {
-	return _topPromoted;
+	const auto old = std::exchange(_topPromoted, promoted);
+	if (_topPromoted) {
+		histories().requestDialogEntry(_topPromoted);
+		_topPromoted->cacheTopPromotion(true, type, message);
+		_topPromoted->requestChatListMessage();
+		session().changes().historyUpdated(
+			_topPromoted,
+			HistoryUpdate::Flag::TopPromoted);
+	}
+	if (changed && old) {
+		session().changes().historyUpdated(
+			old,
+			HistoryUpdate::Flag::TopPromoted);
+	}
 }
 
 bool Session::updateWallpapers(const MTPaccount_WallPapers &data) {
diff --git a/Telegram/SourceFiles/data/data_session.h b/Telegram/SourceFiles/data/data_session.h
index 16fa66e42..c78e0fdb6 100644
--- a/Telegram/SourceFiles/data/data_session.h
+++ b/Telegram/SourceFiles/data/data_session.h
@@ -180,6 +180,11 @@ public:
 
 	void deleteConversationLocally(not_null<PeerData*> peer);
 
+	void newMessageSent(not_null<History*> history);
+	[[nodiscard]] rpl::producer<not_null<History*>> newMessageSent() const;
+	void cancelForwarding(not_null<History*> history);
+	[[nodiscard]] rpl::producer<not_null<History*>> forwardDraftUpdates() const;
+
 	void registerSendAction(
 		not_null<History*> history,
 		not_null<UserData*> user,
@@ -624,10 +629,9 @@ public:
 	MessageIdsList takeMimeForwardIds();
 
 	void setTopPromoted(
-		PeerData *promoted,
+		History *promoted,
 		const QString &type,
 		const QString &message);
-	PeerData *topPromoted() const;
 
 	bool updateWallpapers(const MTPaccount_WallPapers &data);
 	void removeWallpaper(const WallPaper &paper);
@@ -742,8 +746,6 @@ private:
 		not_null<Folder*> folder,
 		const MTPDfolder &data);
 
-	void userIsContactUpdated(not_null<UserData*> user);
-
 	void setPinnedFromDialog(const Dialogs::Key &key, bool pinned);
 
 	NotifySettings &defaultNotifySettings(not_null<const PeerData*> peer);
@@ -878,6 +880,8 @@ private:
 	rpl::event_stream<not_null<WebPageData*>> _webpageUpdates;
 	rpl::event_stream<not_null<ChannelData*>> _channelDifferenceTooLong;
 	rpl::event_stream<not_null<History*>> _historyOutboxReads;
+	rpl::event_stream<not_null<History*>> _newMessageSent;
+	rpl::event_stream<not_null<History*>> _forwardDraftUpdated;
 
 	base::flat_multi_map<TimeId, not_null<PollData*>> _pollsClosings;
 	base::Timer _pollsClosingTimer;
@@ -893,7 +897,7 @@ private:
 
 	base::flat_set<not_null<ViewElement*>> _heavyViewParts;
 
-	PeerData *_topPromoted = nullptr;
+	History *_topPromoted = nullptr;
 
 	NotifySettings _defaultUserNotifySettings;
 	NotifySettings _defaultChatNotifySettings;
diff --git a/Telegram/SourceFiles/data/data_user.cpp b/Telegram/SourceFiles/data/data_user.cpp
index d4e8f5b1c..8bf8fc1df 100644
--- a/Telegram/SourceFiles/data/data_user.cpp
+++ b/Telegram/SourceFiles/data/data_user.cpp
@@ -7,9 +7,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "data/data_user.h"
 
-#include "observer_peer.h"
 #include "storage/localstorage.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "ui/text_options.h"
 #include "apiwrap.h"
 #include "lang/lang_keys.h"
@@ -20,7 +20,7 @@ namespace {
 // User with hidden last seen stays online in UI for such amount of seconds.
 constexpr auto kSetOnlineAfterActivity = TimeId(30);
 
-using UpdateFlag = Notify::PeerUpdate::Flag;
+using UpdateFlag = Data::PeerUpdate::Flag;
 
 } // namespace
 
@@ -65,9 +65,7 @@ void UserData::setIsContact(bool is) {
 		: ContactStatus::NotContact;
 	if (_contactStatus != status) {
 		_contactStatus = status;
-		Notify::peerUpdatedDelayed(
-			this,
-			Notify::PeerUpdate::Flag::UserIsContact);
+		session().changes().peerUpdated(this, UpdateFlag::IsContact);
 	}
 }
 
@@ -92,16 +90,16 @@ void UserData::setUnavailableReasons(
 		std::vector<Data::UnavailableReason> &&reasons) {
 	if (_unavailableReasons != reasons) {
 		_unavailableReasons = std::move(reasons);
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			this,
-			Notify::PeerUpdate::Flag::UnavailableReasonChanged);
+			UpdateFlag::UnavailableReason);
 	}
 }
 
 void UserData::setCommonChatsCount(int count) {
 	if (_commonChatsCount != count) {
 		_commonChatsCount = count;
-		Notify::peerUpdatedDelayed(this, UpdateFlag::UserCommonChatsChanged);
+		session().changes().peerUpdated(this, UpdateFlag::CommonChats);
 	}
 }
 
@@ -213,10 +211,10 @@ void UserData::madeAction(TimeId when) {
 		return;
 	} else if (onlineTill <= 0 && -onlineTill < when) {
 		onlineTill = -when - kSetOnlineAfterActivity;
-		Notify::peerUpdatedDelayed(this, Notify::PeerUpdate::Flag::UserOnlineChanged);
+		session().changes().peerUpdated(this, UpdateFlag::OnlineStatus);
 	} else if (onlineTill > 0 && onlineTill < when + 1) {
 		onlineTill = when + kSetOnlineAfterActivity;
-		Notify::peerUpdatedDelayed(this, Notify::PeerUpdate::Flag::UserOnlineChanged);
+		session().changes().peerUpdated(this, UpdateFlag::OnlineStatus);
 	}
 }
 
@@ -241,14 +239,14 @@ void UserData::setIsBlocked(bool is) {
 		} else {
 			_fullFlags.remove(MTPDuserFull::Flag::f_blocked);
 		}
-		Notify::peerUpdatedDelayed(this, UpdateFlag::UserIsBlocked);
+		session().changes().peerUpdated(this, UpdateFlag::IsBlocked);
 	}
 }
 
 void UserData::setCallsStatus(CallsStatus callsStatus) {
 	if (callsStatus != _callsStatus) {
 		_callsStatus = callsStatus;
-		Notify::peerUpdatedDelayed(this, UpdateFlag::UserHasCalls);
+		session().changes().peerUpdated(this, UpdateFlag::HasCalls);
 	}
 }
 
diff --git a/Telegram/SourceFiles/data/stickers/data_stickers.cpp b/Telegram/SourceFiles/data/stickers/data_stickers.cpp
index b6344c616..39bbcb5e5 100644
--- a/Telegram/SourceFiles/data/stickers/data_stickers.cpp
+++ b/Telegram/SourceFiles/data/stickers/data_stickers.cpp
@@ -62,6 +62,119 @@ rpl::producer<> Stickers::savedGifsUpdated() const {
 	return _savedGifsUpdated.events();
 }
 
+void Stickers::incrementSticker(not_null<DocumentData*> document) {
+	if (!document->sticker()
+		|| document->sticker()->set.type() == mtpc_inputStickerSetEmpty) {
+		return;
+	}
+
+	bool writeRecentStickers = false;
+	auto &sets = setsRef();
+	auto it = sets.find(Data::Stickers::CloudRecentSetId);
+	if (it == sets.cend()) {
+		if (it == sets.cend()) {
+			it = sets.emplace(
+				Data::Stickers::CloudRecentSetId,
+				std::make_unique<Data::StickersSet>(
+					&session().data(),
+					Data::Stickers::CloudRecentSetId,
+					uint64(0),
+					tr::lng_recent_stickers(tr::now),
+					QString(),
+					0, // count
+					0, // hash
+					MTPDstickerSet_ClientFlag::f_special | 0,
+					TimeId(0))).first;
+		} else {
+			it->second->title = tr::lng_recent_stickers(tr::now);
+		}
+	}
+	const auto set = it->second.get();
+	auto removedFromEmoji = std::vector<not_null<EmojiPtr>>();
+	auto index = set->stickers.indexOf(document);
+	if (index > 0) {
+		if (set->dates.empty()) {
+			session().api().requestRecentStickersForce();
+		} else {
+			Assert(set->dates.size() == set->stickers.size());
+			set->dates.erase(set->dates.begin() + index);
+		}
+		set->stickers.removeAt(index);
+		for (auto i = set->emoji.begin(); i != set->emoji.end();) {
+			if (const auto index = i->indexOf(document); index >= 0) {
+				removedFromEmoji.emplace_back(i.key());
+				i->removeAt(index);
+				if (i->isEmpty()) {
+					i = set->emoji.erase(i);
+					continue;
+				}
+			}
+			++i;
+		}
+	}
+	if (index) {
+		if (set->dates.size() == set->stickers.size()) {
+			set->dates.insert(set->dates.begin(), base::unixtime::now());
+		}
+		set->stickers.push_front(document);
+		if (const auto emojiList = getEmojiListFromSet(document)) {
+			for (const auto emoji : *emojiList) {
+				set->emoji[emoji].push_front(document);
+			}
+		} else if (!removedFromEmoji.empty()) {
+			for (const auto emoji : removedFromEmoji) {
+				set->emoji[emoji].push_front(document);
+			}
+		} else {
+			session().api().requestRecentStickersForce();
+		}
+
+		writeRecentStickers = true;
+	}
+
+	// Remove that sticker from old recent, now it is in cloud recent stickers.
+	bool writeOldRecent = false;
+	auto &recent = getRecentPack();
+	for (auto i = recent.begin(), e = recent.end(); i != e; ++i) {
+		if (i->first == document) {
+			writeOldRecent = true;
+			recent.erase(i);
+			break;
+		}
+	}
+	while (!recent.isEmpty() && set->stickers.size() + recent.size() > Global::StickersRecentLimit()) {
+		writeOldRecent = true;
+		recent.pop_back();
+	}
+
+	if (writeOldRecent) {
+		session().local().writeSettings();
+	}
+
+	// Remove that sticker from custom stickers, now it is in cloud recent stickers.
+	bool writeInstalledStickers = false;
+	auto customIt = sets.find(Data::Stickers::CustomSetId);
+	if (customIt != sets.cend()) {
+		const auto custom = customIt->second.get();
+		int removeIndex = custom->stickers.indexOf(document);
+		if (removeIndex >= 0) {
+			custom->stickers.removeAt(removeIndex);
+			if (custom->stickers.isEmpty()) {
+				sets.erase(customIt);
+			}
+			writeInstalledStickers = true;
+		}
+	}
+
+	if (writeInstalledStickers) {
+		session().local().writeInstalledStickers();
+	}
+	if (writeRecentStickers) {
+		session().local().writeRecentStickers();
+	}
+	notifyRecentUpdated();
+}
+
 void Stickers::addSavedGif(not_null<DocumentData*> document) {
 	const auto index = _savedGifs.indexOf(document);
 	if (!index) {
diff --git a/Telegram/SourceFiles/data/stickers/data_stickers.h b/Telegram/SourceFiles/data/stickers/data_stickers.h
index 9abdcf7ac..c846a96bd 100644
--- a/Telegram/SourceFiles/data/stickers/data_stickers.h
+++ b/Telegram/SourceFiles/data/stickers/data_stickers.h
@@ -55,6 +55,8 @@ public:
 	void notifySavedGifsUpdated();
 	[[nodiscard]] rpl::producer<> savedGifsUpdated() const;
 
+	void incrementSticker(not_null<DocumentData*> document);
+
 	bool updateNeeded(crl::time now) const {
 		return updateNeeded(_lastUpdate, now);
 	}
diff --git a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
index 0b336ce3a..10bcada04 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
@@ -30,6 +30,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_histories.h"
 #include "data/data_chat_filters.h"
 #include "data/data_cloud_file.h"
+#include "data/data_changes.h"
 #include "data/stickers/data_stickers.h"
 #include "base/unixtime.h"
 #include "lang/lang_keys.h"
@@ -38,7 +39,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/storage_account.h"
 #include "apiwrap.h"
 #include "window/themes/window_theme.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "window/notifications_manager.h"
 #include "window/window_session_controller.h"
@@ -223,36 +223,40 @@ InnerWidget::InnerWidget(
 		}
 	});
 
-	using UpdateFlag = Notify::PeerUpdate::Flag;
-	auto changes = UpdateFlag::ChatPinnedChanged
-		| UpdateFlag::NameChanged
-		| UpdateFlag::PhotoChanged
-		| UpdateFlag::UserIsContact
-		| UpdateFlag::UserOccupiedChanged
-		| UpdateFlag::MigrationChanged;
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(changes, [=](const Notify::PeerUpdate &update) {
-		if (update.flags & UpdateFlag::ChatPinnedChanged) {
+	session().changes().historyUpdates(
+		Data::HistoryUpdate::Flag::IsPinned
+		| Data::HistoryUpdate::Flag::ChatOccupied
+	) | rpl::start_with_next([=](const Data::HistoryUpdate &update) {
+		if (update.flags & Data::HistoryUpdate::Flag::IsPinned) {
 			stopReorderPinned();
 		}
-		if (update.flags & UpdateFlag::NameChanged) {
+		if (update.flags & Data::HistoryUpdate::Flag::ChatOccupied) {
 			this->update();
+			_updated.fire({});
 		}
-		if (update.flags & (UpdateFlag::PhotoChanged | UpdateFlag::UserOccupiedChanged)) {
+	}, lifetime());
+
+	using UpdateFlag = Data::PeerUpdate::Flag;
+	session().changes().peerUpdates(
+		UpdateFlag::Name
+		| UpdateFlag::Photo
+		| UpdateFlag::IsContact
+		| UpdateFlag::Migration
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		if (update.flags & (UpdateFlag::Name | UpdateFlag::Photo)) {
 			this->update();
-			emit controller->content()->dialogsUpdated();
+			_updated.fire({});
 		}
-		if (update.flags & UpdateFlag::UserIsContact) {
-			if (update.peer->isUser()) {
-				// contactsNoChatsList could've changed.
-				Ui::PostponeCall(this, [=] { refresh(); });
-			}
+		if (update.flags & UpdateFlag::IsContact) {
+			// contactsNoChatsList could've changed.
+			Ui::PostponeCall(this, [=] { refresh(); });
 		}
-		if (update.flags & UpdateFlag::MigrationChanged) {
+		if (update.flags & UpdateFlag::Migration) {
 			if (const auto chat = update.peer->asChat()) {
 				handleChatMigration(chat);
 			}
 		}
-	}));
+	}, lifetime());
 
 	_controller->activeChatEntryValue(
 	) | rpl::combine_previous(
@@ -1498,7 +1502,7 @@ void InnerWidget::removeDialog(Key key) {
 		refresh();
 	}
 
-	emit _controller->content()->dialogsUpdated();
+	_updated.fire({});
 
 	refresh();
 }
@@ -1963,6 +1967,10 @@ auto InnerWidget::chosenRow() const -> rpl::producer<ChosenRow> {
 	return _chosenRow.events();
 }
 
+rpl::producer<> InnerWidget::updated() const {
+	return _updated.events();
+}
+
 rpl::producer<> InnerWidget::listBottomReached() const {
 	return _listBottomReached.events();
 }
@@ -2948,16 +2956,15 @@ MsgId InnerWidget::lastSearchMigratedId() const {
 }
 
 void InnerWidget::setupOnlineStatusCheck() {
-	using namespace Notify;
-	subscribe(PeerUpdated(), PeerUpdatedHandler(
-		PeerUpdate::Flag::UserOnlineChanged,
-		[=](const PeerUpdate &update) { userOnlineUpdated(update); }));
+	session().changes().peerUpdates(
+		Data::PeerUpdate::Flag::OnlineStatus
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		userOnlineUpdated(update.peer);
+	}, lifetime());
 }
 
-void InnerWidget::userOnlineUpdated(const Notify::PeerUpdate &update) {
-	const auto user = update.peer->isSelf()
-		? nullptr
-		: update.peer->asUser();
+void InnerWidget::userOnlineUpdated(not_null<PeerData*> peer) {
+	const auto user = peer->isSelf() ? nullptr : peer->asUser();
 	if (!user) {
 		return;
 	}
diff --git a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
index 8028bd752..ad0824bbd 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
+++ b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
@@ -30,10 +30,6 @@ namespace Window {
 class SessionController;
 } // namespace Window
 
-namespace Notify {
-struct PeerUpdate;
-} // namespace Notify
-
 namespace Data {
 class CloudImageView;
 } // namespace Data
@@ -131,7 +127,8 @@ public:
 
 	base::Observable<UserData*> searchFromUserChanged;
 
-	rpl::producer<ChosenRow> chosenRow() const;
+	[[nodiscard]] rpl::producer<ChosenRow> chosenRow() const;
+	[[nodiscard]] rpl::producer<> updated() const;
 
 	~InnerWidget();
 
@@ -228,7 +225,7 @@ private:
 
 	int defaultRowTop(not_null<Row*> row) const;
 	void setupOnlineStatusCheck();
-	void userOnlineUpdated(const Notify::PeerUpdate &update);
+	void userOnlineUpdated(not_null<PeerData*> peer);
 
 	void setupShortcuts();
 	RowDescriptor computeJump(
@@ -406,6 +403,7 @@ private:
 	Fn<void()> _loadMoreCallback;
 	rpl::event_stream<> _listBottomReached;
 	rpl::event_stream<ChosenRow> _chosenRow;
+	rpl::event_stream<> _updated;
 
 	base::unique_qptr<Ui::PopupMenu> _menu;
 
diff --git a/Telegram/SourceFiles/dialogs/dialogs_main_list.cpp b/Telegram/SourceFiles/dialogs/dialogs_main_list.cpp
index 168dcb7e2..6ce9ef020 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_main_list.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_main_list.cpp
@@ -7,12 +7,16 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "dialogs/dialogs_main_list.h"
 
-#include "observer_peer.h"
+#include "data/data_changes.h"
+#include "main/main_session.h"
 #include "history/history.h"
 
 namespace Dialogs {
 
-MainList::MainList(FilterId filterId, rpl::producer<int> pinnedLimit)
+MainList::MainList(
+	not_null<Main::Session*> session,
+	FilterId filterId,
+	rpl::producer<int> pinnedLimit)
 : _filterId(filterId)
 , _all(SortMode::Date, filterId)
 , _pinned(filterId, 1) {
@@ -24,12 +28,9 @@ MainList::MainList(FilterId filterId, rpl::producer<int> pinnedLimit)
 		_pinned.setLimit(limit);
 	}, _lifetime);
 
-	Notify::PeerUpdateViewer(
-		Notify::PeerUpdate::Flag::NameChanged
-	) | rpl::start_with_next([=](const Notify::PeerUpdate &update) {
-		const auto peer = update.peer;
-		const auto &oldLetters = update.oldNameFirstLetters;
-		_all.peerNameChanged(_filterId, peer, oldLetters);
+	session->changes().realtimeNameUpdates(
+	) | rpl::start_with_next([=](const Data::NameUpdate &update) {
+		_all.peerNameChanged(_filterId, update.peer, update.oldFirstLetters);
 	}, _lifetime);
 }
 
diff --git a/Telegram/SourceFiles/dialogs/dialogs_main_list.h b/Telegram/SourceFiles/dialogs/dialogs_main_list.h
index c9ac27480..c9aef1edf 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_main_list.h
+++ b/Telegram/SourceFiles/dialogs/dialogs_main_list.h
@@ -10,11 +10,18 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "dialogs/dialogs_indexed_list.h"
 #include "dialogs/dialogs_pinned_list.h"
 
+namespace Main {
+class Session;
+} // namespace Main
+
 namespace Dialogs {
 
 class MainList final {
 public:
-	MainList(FilterId filterId, rpl::producer<int> pinnedLimit);
+	MainList(
+		not_null<Main::Session*> session,
+		FilterId filterId,
+		rpl::producer<int> pinnedLimit);
 
 	bool empty() const;
 	bool loaded() const;
diff --git a/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.cpp b/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.cpp
index 7f0206ace..770b6d759 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.cpp
@@ -12,7 +12,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "apiwrap.h"
 
diff --git a/Telegram/SourceFiles/dialogs/dialogs_widget.cpp b/Telegram/SourceFiles/dialogs/dialogs_widget.cpp
index 824e84c0f..da73edb44 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_widget.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_widget.cpp
@@ -176,6 +176,11 @@ Widget::Widget(
 , _singleMessageSearch(&controller->session()) {
 	_inner = _scroll->setOwnedWidget(object_ptr<InnerWidget>(this, controller));
 
+	_inner->updated(
+	) | rpl::start_with_next([=] {
+		onListScroll();
+	}, lifetime());
+
 	rpl::combine(
 		session().api().dialogsLoadMayBlockByDate(),
 		session().api().dialogsLoadBlockedByDate()
@@ -183,6 +188,11 @@ Widget::Widget(
 		refreshLoadMoreButton(mayBlock, isBlocked);
 	}, lifetime());
 
+	session().data().newMessageSent(
+	) | rpl::start_with_next([=] {
+		jumpToTop();
+	}, lifetime());
+
 	fullSearchRefreshOn(session().settings().skipArchiveInSearchChanges(
 	) | rpl::map([] { return rpl::empty_value(); }));
 
diff --git a/Telegram/SourceFiles/facades.cpp b/Telegram/SourceFiles/facades.cpp
index af71ca3a1..d101f9df6 100644
--- a/Telegram/SourceFiles/facades.cpp
+++ b/Telegram/SourceFiles/facades.cpp
@@ -17,7 +17,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/platform/base_platform_info.h"
 #include "data/data_peer.h"
 #include "data/data_user.h"
-#include "observer_peer.h"
 #include "mainwindow.h"
 #include "mainwidget.h"
 #include "apiwrap.h"
@@ -338,7 +337,6 @@ namespace internal {
 
 struct Data {
 	SingleQueuedInvokation HandleUnreadCounterUpdate = { [] { Core::App().call_handleUnreadCounterUpdate(); } };
-	SingleQueuedInvokation HandleDelayedPeerUpdates = { [] { Core::App().call_handleDelayedPeerUpdates(); } };
 
 	Adaptive::WindowLayout AdaptiveWindowLayout = Adaptive::WindowLayout::Normal;
 	Adaptive::ChatLayout AdaptiveChatLayout = Adaptive::ChatLayout::Normal;
@@ -458,7 +456,6 @@ void finish() {
 }
 
 DefineRefVar(Global, SingleQueuedInvokation, HandleUnreadCounterUpdate);
-DefineRefVar(Global, SingleQueuedInvokation, HandleDelayedPeerUpdates);
 
 DefineVar(Global, Adaptive::WindowLayout, AdaptiveWindowLayout);
 DefineVar(Global, Adaptive::ChatLayout, AdaptiveChatLayout);
diff --git a/Telegram/SourceFiles/facades.h b/Telegram/SourceFiles/facades.h
index c913ab35a..7d5be71e5 100644
--- a/Telegram/SourceFiles/facades.h
+++ b/Telegram/SourceFiles/facades.h
@@ -145,7 +145,6 @@ void start();
 void finish();
 
 DeclareRefVar(SingleQueuedInvokation, HandleUnreadCounterUpdate);
-DeclareRefVar(SingleQueuedInvokation, HandleDelayedPeerUpdates);
 
 DeclareVar(Adaptive::WindowLayout, AdaptiveWindowLayout);
 DeclareVar(Adaptive::ChatLayout, AdaptiveChatLayout);
diff --git a/Telegram/SourceFiles/history/admin_log/history_admin_log_section.h b/Telegram/SourceFiles/history/admin_log/history_admin_log_section.h
index c9106674e..33a1b06c7 100644
--- a/Telegram/SourceFiles/history/admin_log/history_admin_log_section.h
+++ b/Telegram/SourceFiles/history/admin_log/history_admin_log_section.h
@@ -12,10 +12,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "history/admin_log/history_admin_log_item.h"
 #include "mtproto/sender.h"
 
-namespace Notify {
-struct PeerUpdate;
-} // namespace Notify
-
 namespace Ui {
 class ScrollArea;
 class PlainShadow;
diff --git a/Telegram/SourceFiles/history/history.cpp b/Telegram/SourceFiles/history/history.cpp
index 1bef57046..79686904a 100644
--- a/Telegram/SourceFiles/history/history.cpp
+++ b/Telegram/SourceFiles/history/history.cpp
@@ -18,6 +18,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_session.h"
 #include "data/data_media_types.h"
 #include "data/data_channel_admins.h"
+#include "data/data_changes.h"
 #include "data/data_chat_filters.h"
 #include "data/data_scheduled_messages.h"
 #include "data/data_folder.h"
@@ -30,7 +31,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "apiwrap.h"
 #include "mainwidget.h"
 #include "mainwindow.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "window/notifications_manager.h"
 #include "calls/calls_instance.h"
@@ -65,6 +65,8 @@ constexpr auto kSetMyActionForMs = 10000;
 constexpr auto kNewBlockEachMessage = 50;
 constexpr auto kSkipCloudDraftsFor = TimeId(3);
 
+using UpdateFlag = Data::HistoryUpdate::Flag;
+
 } // namespace
 
 History::History(not_null<Data::Session*> owner, PeerId peerId)
@@ -874,7 +876,7 @@ void History::eraseFromUnreadMentions(MsgId msgId) {
 	if (_unreadMentionsCount && *_unreadMentionsCount > 0) {
 		setUnreadMentionsCount(*_unreadMentionsCount - 1);
 	}
-	Notify::peerUpdatedDelayed(peer, Notify::PeerUpdate::Flag::UnreadMentionsChanged);
+	session().changes().historyUpdated(this, UpdateFlag::UnreadMentions);
 }
 
 void History::addUnreadMentionsSlice(const MTPmessages_Messages &result) {
@@ -929,7 +931,7 @@ void History::addUnreadMentionsSlice(const MTPmessages_Messages &result) {
 		count = _unreadMentions.size();
 	}
 	setUnreadMentionsCount(count);
-	Notify::peerUpdatedDelayed(peer, Notify::PeerUpdate::Flag::UnreadMentionsChanged);
+	session().changes().historyUpdated(this, UpdateFlag::UnreadMentions);
 }
 
 not_null<HistoryItem*> History::addNewToBack(
@@ -987,7 +989,9 @@ not_null<HistoryItem*> History::addNewToBack(
 					lastAuthors->push_front(user);
 				}
 				if (auto megagroup = peer->asMegagroup()) {
-					Notify::peerUpdatedDelayed(peer, Notify::PeerUpdate::Flag::MembersChanged);
+					session().changes().peerUpdated(
+						peer,
+						Data::PeerUpdate::Flag::Members);
 					owner().addNewMegagroupParticipant(megagroup, user);
 				}
 			}
@@ -1075,7 +1079,9 @@ void History::applyServiceChanges(
 				if (const auto user = owner().userLoaded(userId.v)) {
 					if (!base::contains(mgInfo->lastParticipants, user)) {
 						mgInfo->lastParticipants.push_front(user);
-						Notify::peerUpdatedDelayed(peer, Notify::PeerUpdate::Flag::MembersChanged);
+						session().changes().peerUpdated(
+							peer,
+							Data::PeerUpdate::Flag::Members);
 						owner().addNewMegagroupParticipant(megagroup, user);
 					}
 					if (user->isBot()) {
@@ -1097,7 +1103,9 @@ void History::applyServiceChanges(
 			if (auto user = item->from()->asUser()) {
 				if (!base::contains(mgInfo->lastParticipants, user)) {
 					mgInfo->lastParticipants.push_front(user);
-					Notify::peerUpdatedDelayed(peer, Notify::PeerUpdate::Flag::MembersChanged);
+					session().changes().peerUpdated(
+						peer,
+						Data::PeerUpdate::Flag::Members);
 					owner().addNewMegagroupParticipant(megagroup, user);
 				}
 				if (user->isBot()) {
@@ -1132,7 +1140,9 @@ void History::applyServiceChanges(
 					[](not_null<UserData*> user) { return user.get(); });
 				if (i != mgInfo->lastParticipants.end()) {
 					mgInfo->lastParticipants.erase(i);
-					Notify::peerUpdatedDelayed(peer, Notify::PeerUpdate::Flag::MembersChanged);
+					session().changes().peerUpdated(
+						peer,
+						Data::PeerUpdate::Flag::Members);
 				}
 				owner().removeMegagroupParticipant(megagroup, user);
 				if (megagroup->membersCount() > 1) {
@@ -1146,7 +1156,9 @@ void History::applyServiceChanges(
 					if (megagroup->adminsCount() > 1) {
 						megagroup->setAdminsCount(megagroup->adminsCount() - 1);
 					}
-					Notify::peerUpdatedDelayed(peer, Notify::PeerUpdate::Flag::AdminsChanged);
+					session().changes().peerUpdated(
+						peer,
+						Data::PeerUpdate::Flag::Admins);
 				}
 				mgInfo->bots.remove(user);
 				if (mgInfo->bots.empty() && mgInfo->botStatus > 0) {
@@ -1310,22 +1322,14 @@ void History::registerLocalMessage(not_null<HistoryItem*> item) {
 	Expects(IsClientMsgId(item->id));
 
 	_localMessages.emplace(item);
-	if (peer->isChannel()) {
-		Notify::peerUpdatedDelayed(
-			peer,
-			Notify::PeerUpdate::Flag::ChannelLocalMessages);
-	}
+	session().changes().historyUpdated(this, UpdateFlag::LocalMessages);
 }
 
 void History::unregisterLocalMessage(not_null<HistoryItem*> item) {
 	const auto removed = _localMessages.remove(item);
 	Assert(removed);
 
-	if (peer->isChannel()) {
-		Notify::peerUpdatedDelayed(
-			peer,
-			Notify::PeerUpdate::Flag::ChannelLocalMessages);
-	}
+	session().changes().historyUpdated(this, UpdateFlag::LocalMessages);
 }
 
 HistoryItem *History::latestSendingMessage() const {
@@ -1805,9 +1809,7 @@ void History::setUnreadCount(int newUnreadCount) {
 		if (wasForBadge != (unreadCountForBadge() > 0)) {
 			owner().chatsFilters().refreshHistory(this);
 		}
-		Notify::peerUpdatedDelayed(
-			peer,
-			Notify::PeerUpdate::Flag::UnreadViewChanged);
+		session().changes().historyUpdated(this, UpdateFlag::UnreadView);
 	});
 	const auto notifier = unreadStateChangeNotifier(true);
 	_unreadCount = newUnreadCount;
@@ -1844,9 +1846,7 @@ void History::setUnreadMark(bool unread) {
 			owner().chatsFilters().refreshHistory(this);
 			updateChatListEntry();
 		}
-		Notify::peerUpdatedDelayed(
-			peer,
-			Notify::PeerUpdate::Flag::UnreadViewChanged);
+		session().changes().historyUpdated(this, UpdateFlag::UnreadView);
 	});
 	const auto notifier = unreadStateChangeNotifier(noUnreadMessages);
 	_unreadMark = unread;
@@ -1886,9 +1886,9 @@ bool History::changeMute(bool newMute) {
 			owner().chatsFilters().refreshHistory(this);
 			updateChatListEntry();
 		}
-		Notify::peerUpdatedDelayed(
+		session().changes().peerUpdated(
 			peer,
-			Notify::PeerUpdate::Flag::NotificationsEnabled);
+			Data::PeerUpdate::Flag::Notifications);
 	});
 	const auto notify = (unreadCountForBadge() > 0);
 	const auto notifier = unreadStateChangeNotifier(notify);
@@ -1986,9 +1986,7 @@ void History::setFolderPointer(Data::Folder *folder) {
 	if (folder) {
 		folder->registerOne(this);
 	}
-	Notify::peerUpdatedDelayed(
-		peer,
-		Notify::PeerUpdate::Flag::FolderChanged);
+	session().changes().historyUpdated(this, UpdateFlag::Folder);
 }
 
 void History::applyPinnedUpdate(const MTPDupdateDialogPinned &data) {
@@ -3294,9 +3292,7 @@ void History::applyGroupAdminChanges(const base::flat_set<UserId> &changes) {
 }
 
 void History::changedChatListPinHook() {
-	Notify::peerUpdatedDelayed(
-		peer,
-		Notify::PeerUpdate::Flag::ChatPinnedChanged);
+	session().changes().historyUpdated(this, UpdateFlag::IsPinned);
 }
 
 void History::removeBlock(not_null<HistoryBlock*> block) {
diff --git a/Telegram/SourceFiles/history/history_item.cpp b/Telegram/SourceFiles/history/history_item.cpp
index 354dd4f1f..f63774e09 100644
--- a/Telegram/SourceFiles/history/history_item.cpp
+++ b/Telegram/SourceFiles/history/history_item.cpp
@@ -34,6 +34,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/crash_reports.h"
 #include "base/unixtime.h"
 #include "data/data_scheduled_messages.h" // kScheduledUntilOnlineTimestamp
+#include "data/data_changes.h"
 #include "data/data_session.h"
 #include "data/data_messages.h"
 #include "data/data_media_types.h"
@@ -41,7 +42,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
-#include "observer_peer.h"
 #include "facades.h"
 #include "styles/style_dialogs.h"
 #include "styles/style_history.h"
@@ -725,11 +725,9 @@ void HistoryItem::sendFailed() {
 
 	_clientFlags = (_clientFlags | MTPDmessage_ClientFlag::f_failed)
 		& ~MTPDmessage_ClientFlag::f_sending;
-	if (history()->peer->isChannel()) {
-		Notify::peerUpdatedDelayed(
-			history()->peer,
-			Notify::PeerUpdate::Flag::ChannelLocalMessages);
-	}
+	history()->session().changes().historyUpdated(
+		history(),
+		Data::HistoryUpdate::Flag::LocalMessages);
 }
 
 bool HistoryItem::needCheck() const {
diff --git a/Telegram/SourceFiles/history/history_message.cpp b/Telegram/SourceFiles/history/history_message.cpp
index b05012e37..8e9baca51 100644
--- a/Telegram/SourceFiles/history/history_message.cpp
+++ b/Telegram/SourceFiles/history/history_message.cpp
@@ -32,9 +32,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "layout.h"
 #include "window/notifications_manager.h"
 #include "window/window_session_controller.h"
-#include "observer_peer.h"
 #include "storage/storage_shared_media.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "data/data_game.h"
 #include "data/data_media_types.h"
 #include "data/data_channel.h"
@@ -1152,9 +1152,9 @@ void HistoryMessage::contributeToSlowmode(TimeId realDate) {
 void HistoryMessage::addToUnreadMentions(UnreadMentionType type) {
 	if (IsServerMsgId(id) && isUnreadMention()) {
 		if (history()->addToUnreadMentions(id, type)) {
-			Notify::peerUpdatedDelayed(
-				history()->peer,
-				Notify::PeerUpdate::Flag::UnreadMentionsChanged);
+			history()->session().changes().historyUpdated(
+				history(),
+				Data::HistoryUpdate::Flag::UnreadMentions);
 		}
 	}
 }
diff --git a/Telegram/SourceFiles/history/history_widget.cpp b/Telegram/SourceFiles/history/history_widget.cpp
index 5bf028576..fdceb28da 100644
--- a/Telegram/SourceFiles/history/history_widget.cpp
+++ b/Telegram/SourceFiles/history/history_widget.cpp
@@ -30,6 +30,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/event_filter.h"
 #include "base/unixtime.h"
 #include "base/call_delayed.h"
+#include "data/data_changes.h"
 #include "data/data_drafts.h"
 #include "data/data_session.h"
 #include "data/data_web_page.h"
@@ -78,7 +79,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "apiwrap.h"
 #include "history/view/history_view_top_bar_widget.h"
 #include "history/view/history_view_contact_status.h"
-#include "observer_peer.h"
 #include "base/qthelp_regex.h"
 #include "ui/widgets/popup_menu.h"
 #include "ui/text_options.h"
@@ -162,9 +162,9 @@ object_ptr<Ui::FlatButton> SetupDiscussButton(
 		return history ? history->peer->asChannel() : nullptr;
 	}) | rpl::map([=](ChannelData *channel) -> rpl::producer<ChannelData*> {
 		if (channel && channel->isBroadcast()) {
-			return PeerUpdateValue(
+			return channel->session().changes().peerFlagsValue(
 				channel,
-				Notify::PeerUpdate::Flag::ChannelLinkedChat
+				Data::PeerUpdate::Flag::ChannelLinkedChat
 			) | rpl::map([=] {
 				return channel->linkedChat();
 			});
@@ -175,11 +175,19 @@ object_ptr<Ui::FlatButton> SetupDiscussButton(
 	) | rpl::map([=](ChannelData *chat)
 	-> rpl::producer<std::tuple<int, bool>> {
 		if (chat) {
-			return PeerUpdateValue(
-				chat,
-				Notify::PeerUpdate::Flag::UnreadViewChanged
-				| Notify::PeerUpdate::Flag::NotificationsEnabled
-				| Notify::PeerUpdate::Flag::ChannelAmIn
+			using UpdateFlag = Data::PeerUpdate::Flag;
+			auto to_empty = rpl::map([=] { return rpl::empty_value(); });
+			return rpl::merge(
+				chat->session().changes().historyUpdates(
+					Data::HistoryUpdate::Flag::UnreadView
+				) | rpl::filter([=](const Data::HistoryUpdate &update) {
+					return (update.history->peer == chat);
+				}) | to_empty,
+
+				chat->session().changes().peerFlagsValue(
+					chat,
+					UpdateFlag::Notifications | UpdateFlag::ChannelAmIn
+				) | to_empty
 			) | rpl::map([=] {
 				const auto history = chat->amIn()
 					? chat->owner().historyLoaded(chat)
@@ -546,83 +554,111 @@ HistoryWidget::HistoryWidget(
 		}
 	}, lifetime());
 
+	session().data().forwardDraftUpdates(
+	) | rpl::filter([=](not_null<History*> history) {
+		return (_history == history.get());
+	}) | rpl::start_with_next([=](not_null<History*> history) {
+		updateForwarding();
+	}, lifetime());
+
+	session().data().newMessageSent(
+	) | rpl::filter([=](not_null<History*> history) {
+		return (_history == history.get());
+	}) | rpl::start_with_next([=] {
+		synteticScrollToY(_scroll->scrollTopMax());
+	}, lifetime());
+
 	subscribe(Media::Player::instance()->switchToNextNotifier(), [this](const Media::Player::Instance::Switch &pair) {
 		if (pair.from.type() == AudioMsgId::Type::Voice) {
 			scrollToCurrentVoiceMessage(pair.from.contextId(), pair.to);
 		}
 	});
-	using UpdateFlag = Notify::PeerUpdate::Flag;
-	auto changes = UpdateFlag::RightsChanged
-		| UpdateFlag::UnreadMentionsChanged
-		| UpdateFlag::UnreadViewChanged
-		| UpdateFlag::MigrationChanged
-		| UpdateFlag::UnavailableReasonChanged
-		| UpdateFlag::PinnedMessageChanged
-		| UpdateFlag::TopPromotedChanged
-		| UpdateFlag::UserIsBlocked
-		| UpdateFlag::AdminsChanged
-		| UpdateFlag::MembersChanged
-		| UpdateFlag::UserOnlineChanged
-		| UpdateFlag::NotificationsEnabled
+
+	session().changes().historyUpdates(
+		Data::HistoryUpdate::Flag::UnreadMentions
+		| Data::HistoryUpdate::Flag::UnreadView
+		| Data::HistoryUpdate::Flag::TopPromoted
+		| Data::HistoryUpdate::Flag::LocalMessages
+	) | rpl::filter([=](const Data::HistoryUpdate &update) {
+		return (update.history->peer.get() == _peer);
+	}) | rpl::map([](const Data::HistoryUpdate &update) {
+		return update.flags;
+	}) | rpl::start_with_next([=](Data::HistoryUpdate::Flags flags) {
+		if (flags & Data::HistoryUpdate::Flag::LocalMessages) {
+			updateSendButtonType();
+		}
+		if (flags & Data::HistoryUpdate::Flag::UnreadMentions) {
+			updateUnreadMentionsVisibility();
+		}
+		if (flags & Data::HistoryUpdate::Flag::UnreadView) {
+			unreadCountUpdated();
+		}
+		if (flags & Data::HistoryUpdate::Flag::TopPromoted) {
+			updateHistoryGeometry();
+			updateControlsVisibility();
+			updateControlsGeometry();
+			this->update();
+		}
+	}, lifetime());
+
+	using UpdateFlag = Data::PeerUpdate::Flag;
+	session().changes().peerUpdates(
+		UpdateFlag::Rights
+		| UpdateFlag::Migration
+		| UpdateFlag::UnavailableReason
+		| UpdateFlag::PinnedMessage
+		| UpdateFlag::IsBlocked
+		| UpdateFlag::Admins
+		| UpdateFlag::Members
+		| UpdateFlag::OnlineStatus
+		| UpdateFlag::Notifications
 		| UpdateFlag::ChannelAmIn
 		| UpdateFlag::ChannelLinkedChat
-		| UpdateFlag::ChannelSlowmode
-		| UpdateFlag::ChannelLocalMessages;
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(changes, [=](const Notify::PeerUpdate &update) {
-		if (update.peer == _peer) {
-			if (update.flags & UpdateFlag::RightsChanged) {
-				checkPreview();
-				updateStickersByEmoji();
+		| UpdateFlag::Slowmode
+	) | rpl::filter([=](const Data::PeerUpdate &update) {
+		return (update.peer.get() == _peer);
+	}) | rpl::map([](const Data::PeerUpdate &update) {
+		return update.flags;
+	}) | rpl::start_with_next([=](Data::PeerUpdate::Flags flags) {
+		if (flags & UpdateFlag::Rights) {
+			checkPreview();
+			updateStickersByEmoji();
+		}
+		if (flags & UpdateFlag::Migration) {
+			handlePeerMigration();
+		}
+		if (flags & UpdateFlag::Notifications) {
+			updateNotifyControls();
+		}
+		if (flags & UpdateFlag::UnavailableReason) {
+			const auto unavailable = _peer->computeUnavailableReason();
+			if (!unavailable.isEmpty()) {
+				controller->showBackFromStack();
+				Ui::show(Box<InformBox>(unavailable));
+				return;
 			}
-			if (update.flags & UpdateFlag::UnreadMentionsChanged) {
-				updateUnreadMentionsVisibility();
-			}
-			if (update.flags & UpdateFlag::UnreadViewChanged) {
-				unreadCountUpdated();
-			}
-			if (update.flags & UpdateFlag::MigrationChanged) {
-				handlePeerMigration();
-			}
-			if (update.flags & UpdateFlag::NotificationsEnabled) {
-				updateNotifyControls();
-			}
-			if (update.flags & UpdateFlag::UnavailableReasonChanged) {
-				const auto unavailable = _peer->computeUnavailableReason();
-				if (!unavailable.isEmpty()) {
-					controller->showBackFromStack();
-					Ui::show(Box<InformBox>(unavailable));
-					return;
-				}
-			}
-			if (update.flags & UpdateFlag::PinnedMessageChanged) {
-				if (pinnedMsgVisibilityUpdated()) {
-					updateHistoryGeometry();
-					updateControlsVisibility();
-					updateControlsGeometry();
-					this->update();
-				}
-			}
-			if (update.flags & UpdateFlag::TopPromotedChanged) {
+		}
+		if (flags & UpdateFlag::PinnedMessage) {
+			if (pinnedMsgVisibilityUpdated()) {
 				updateHistoryGeometry();
 				updateControlsVisibility();
 				updateControlsGeometry();
 				this->update();
 			}
-			if (update.flags & (UpdateFlag::ChannelSlowmode
-				| UpdateFlag::ChannelLocalMessages)) {
-				updateSendButtonType();
-			}
-			if (update.flags & (UpdateFlag::UserIsBlocked
-				| UpdateFlag::AdminsChanged
-				| UpdateFlag::MembersChanged
-				| UpdateFlag::UserOnlineChanged
-				| UpdateFlag::RightsChanged
-				| UpdateFlag::ChannelAmIn
-				| UpdateFlag::ChannelLinkedChat)) {
-				handlePeerUpdate();
-			}
 		}
-	}));
+		if (flags & UpdateFlag::Slowmode) {
+			updateSendButtonType();
+		}
+		if (flags & (UpdateFlag::IsBlocked
+			| UpdateFlag::Admins
+			| UpdateFlag::Members
+			| UpdateFlag::OnlineStatus
+			| UpdateFlag::Rights
+			| UpdateFlag::ChannelAmIn
+			| UpdateFlag::ChannelLinkedChat)) {
+			handlePeerUpdate();
+		}
+	}, lifetime());
 
 	rpl::merge(
 		session().data().defaultUserNotifyUpdates(),
@@ -1074,7 +1110,7 @@ void HistoryWidget::onHashtagOrBotCommandInsert(
 	// Send bot command at once, if it was not inserted by pressing Tab.
 	if (str.at(0) == '/' && method != FieldAutocomplete::ChooseMethod::ByTab) {
 		App::sendBotCommand(_peer, nullptr, str, replyToId());
-		controller()->content()->finishForwarding(Api::SendAction(_history));
+		session().api().finishForwarding(Api::SendAction(_history));
 		setFieldText(_field->getTextWithTagsPart(_field->textCursor().position()));
 	} else {
 		_field->insertTag(str);
@@ -2381,16 +2417,6 @@ void HistoryWidget::unreadMessageAdded(not_null<HistoryItem*> item) {
 	session().notifications().clearFromHistory(_history);
 }
 
-void HistoryWidget::historyToDown(History *history) {
-	history->forgetScrollState();
-	if (auto migrated = history->owner().historyLoaded(history->peer->migrateFrom())) {
-		migrated->forgetScrollState();
-	}
-	if (history == _history) {
-		synteticScrollToY(_scroll->scrollTopMax());
-	}
-}
-
 void HistoryWidget::unreadCountUpdated() {
 	if (_history->chatListUnreadMark()) {
 		crl::on_main(this, [=, history = _history] {
@@ -3151,8 +3177,7 @@ void HistoryWidget::send(Api::SendOptions options) {
 	if (!_keyboard->hasMarkup() && _keyboard->forceReply() && !_kbReplyTo) {
 		toggleKeyboard();
 	}
-	controller()->content()->historyToDown(_history);
-	controller()->content()->dialogsToUp();
+	session().data().newMessageSent(_history);
 }
 
 void HistoryWidget::sendWithModifiers(Qt::KeyboardModifiers modifiers) {
@@ -4093,6 +4118,9 @@ void HistoryWidget::setMembersShowAreaActive(bool active) {
 }
 
 void HistoryWidget::onMembersDropdownShow() {
+	if (!_peer) {
+		return;
+	}
 	if (!_membersDropdown) {
 		_membersDropdown.create(this, st::membersInnerDropdown);
 		_membersDropdown->setOwnedWidget(object_ptr<Profile::GroupMembersWidget>(this, _peer, st::membersInnerItem));
@@ -4856,10 +4884,7 @@ void HistoryWidget::sendFileConfirmed(
 	}
 
 	session().data().sendHistoryChangeNotifications();
-	if (_peer && file->to.peer == _peer->id) {
-		controller()->content()->historyToDown(_history);
-	}
-	controller()->content()->dialogsToUp();
+	session().data().newMessageSent(history);
 }
 
 void HistoryWidget::photoUploaded(
@@ -5591,7 +5616,7 @@ void HistoryWidget::mousePressEvent(QMouseEvent *e) {
 	} else if (_inReplyEditForward) {
 		if (readyToForward()) {
 			const auto items = std::move(_toForward);
-			controller()->content()->cancelForwarding(_history);
+			session().data().cancelForwarding(_history);
 			auto list = ranges::view::all(
 				items
 			) | ranges::view::transform(
@@ -6049,7 +6074,7 @@ void HistoryWidget::replyToMessage(not_null<HistoryItem*> item) {
 		return;
 	}
 
-	controller()->content()->cancelForwarding(_history);
+	session().data().cancelForwarding(_history);
 
 	if (_editMsgId) {
 		if (auto localDraft = _history->localDraft()) {
@@ -6317,7 +6342,7 @@ void HistoryWidget::cancelFieldAreaState() {
 	} else if (_editMsgId) {
 		cancelEdit();
 	} else if (readyToForward()) {
-		controller()->content()->cancelForwarding(_history);
+		session().data().cancelForwarding(_history);
 	} else if (_replyToId) {
 		cancelReply();
 	} else if (_kbReplyTo) {
diff --git a/Telegram/SourceFiles/history/history_widget.h b/Telegram/SourceFiles/history/history_widget.h
index 3815789de..021064db3 100644
--- a/Telegram/SourceFiles/history/history_widget.h
+++ b/Telegram/SourceFiles/history/history_widget.h
@@ -135,8 +135,6 @@ public:
 	void firstLoadMessages();
 	void delayedShowAt(MsgId showAtMsgId);
 
-	void historyToDown(History *history);
-
 	QRect historyRect() const;
 
 	void updateFieldPlaceholder();
diff --git a/Telegram/SourceFiles/history/view/history_view_scheduled_section.h b/Telegram/SourceFiles/history/view/history_view_scheduled_section.h
index 146059209..124b7acef 100644
--- a/Telegram/SourceFiles/history/view/history_view_scheduled_section.h
+++ b/Telegram/SourceFiles/history/view/history_view_scheduled_section.h
@@ -22,10 +22,6 @@ namespace Api {
 struct SendOptions;
 } // namespace Api
 
-namespace Notify {
-struct PeerUpdate;
-} // namespace Notify
-
 namespace Storage {
 struct PreparedList;
 } // namespace Storage
diff --git a/Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp b/Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp
index c1e26fd35..4d2fc67d8 100644
--- a/Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp
+++ b/Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp
@@ -35,9 +35,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
+#include "data/data_changes.h"
 #include "base/unixtime.h"
 #include "support/support_helper.h"
-#include "observer_peer.h"
 #include "apiwrap.h"
 #include "facades.h"
 #include "styles/style_window.h"
@@ -113,20 +113,22 @@ TopBarWidget::TopBarWidget(
 		}, lifetime());
 	}
 
-	using UpdateFlag = Notify::PeerUpdate::Flag;
-	auto flags = UpdateFlag::UserHasCalls
-		| UpdateFlag::UserOnlineChanged
-		| UpdateFlag::MembersChanged
-		| UpdateFlag::UserSupportInfoChanged;
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(flags, [=](const Notify::PeerUpdate &update) {
-		if (update.flags & UpdateFlag::UserHasCalls) {
+	using UpdateFlag = Data::PeerUpdate::Flag;
+	session().changes().peerUpdates(
+		UpdateFlag::HasCalls
+		| UpdateFlag::OnlineStatus
+		| UpdateFlag::Members
+		| UpdateFlag::SupportInfo
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		if (update.flags & UpdateFlag::HasCalls) {
 			if (update.peer->isUser()) {
 				updateControlsVisibility();
 			}
 		} else {
 			updateOnlineDisplay();
 		}
-	}));
+	}, lifetime());
+
 	subscribe(Global::RefPhoneCallsEnabledChanged(), [this] {
 		updateControlsVisibility();
 	});
@@ -286,7 +288,7 @@ bool TopBarWidget::eventFilter(QObject *obj, QEvent *e) {
 			break;
 		}
 	}
-	return TWidget::eventFilter(obj, e);
+	return RpWidget::eventFilter(obj, e);
 }
 
 int TopBarWidget::resizeGetHeight(int newWidth) {
diff --git a/Telegram/SourceFiles/info/info_controller.cpp b/Telegram/SourceFiles/info/info_controller.cpp
index d56199634..1de01a4f7 100644
--- a/Telegram/SourceFiles/info/info_controller.cpp
+++ b/Telegram/SourceFiles/info/info_controller.cpp
@@ -14,7 +14,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "info/info_content_widget.h"
 #include "info/info_memento.h"
 #include "info/media/info_media_widget.h"
-#include "observer_peer.h"
+#include "data/data_changes.h"
 #include "data/data_peer.h"
 #include "data/data_channel.h"
 #include "data/data_chat.h"
@@ -153,22 +153,22 @@ void Controller::setupMigrationViewer() {
 	if (!peer || (!peer->isChat() && !peer->isChannel()) || _migrated) {
 		return;
 	}
-	Notify::PeerUpdateValue(
+	peer->session().changes().peerFlagsValue(
 		peer,
-		Notify::PeerUpdate::Flag::MigrationChanged
-	) | rpl::start_with_next([=] {
-		if (peer->migrateTo() || (peer->migrateFrom() != _migrated)) {
-			const auto window = parentController();
-			const auto section = _section;
-			InvokeQueued(_widget, [=] {
-				window->showSection(
-					Memento(peer, section),
-					Window::SectionShow(
-						Window::SectionShow::Way::Backward,
-						anim::type::instant,
-						anim::activation::background));
-			});
-		}
+		Data::PeerUpdate::Flag::Migration
+	) | rpl::filter([=] {
+		return peer->migrateTo() || (peer->migrateFrom() != _migrated);
+	}) | rpl::start_with_next([=] {
+		const auto window = parentController();
+		const auto section = _section;
+		InvokeQueued(_widget, [=] {
+			window->showSection(
+				Memento(peer, section),
+				Window::SectionShow(
+					Window::SectionShow::Way::Backward,
+					anim::type::instant,
+					anim::activation::background));
+		});
 	}, lifetime());
 }
 
diff --git a/Telegram/SourceFiles/info/info_wrap_widget.cpp b/Telegram/SourceFiles/info/info_wrap_widget.cpp
index 32dda9bd2..c6bac04d4 100644
--- a/Telegram/SourceFiles/info/info_wrap_widget.cpp
+++ b/Telegram/SourceFiles/info/info_wrap_widget.cpp
@@ -29,6 +29,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/confirm_box.h"
 #include "main/main_session.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "data/data_user.h"
 #include "mainwidget.h"
 #include "lang/lang_keys.h"
@@ -482,9 +483,9 @@ void WrapWidget::addProfileCallsButton() {
 		return;
 	}
 
-	Notify::PeerUpdateValue(
+	user->session().changes().peerFlagsValue(
 		user,
-		Notify::PeerUpdate::Flag::UserHasCalls
+		Data::PeerUpdate::Flag::HasCalls
 	) | rpl::filter([=] {
 		return user->hasCalls();
 	}) | rpl::take(
diff --git a/Telegram/SourceFiles/info/profile/info_profile_actions.cpp b/Telegram/SourceFiles/info/profile/info_profile_actions.cpp
index dee907f16..d3c704820 100644
--- a/Telegram/SourceFiles/info/profile/info_profile_actions.cpp
+++ b/Telegram/SourceFiles/info/profile/info_profile_actions.cpp
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_session.h"
 #include "data/data_folder.h"
 #include "data/data_channel.h"
+#include "data/data_changes.h"
 #include "data/data_user.h"
 #include "ui/wrap/vertical_layout.h"
 #include "ui/wrap/padding_wrap.h"
@@ -556,9 +557,9 @@ void ActionsFiller::addBotCommandActions(not_null<UserData*> user) {
 		return QString();
 	};
 	auto hasBotCommandValue = [=](const QString &command) {
-		return Notify::PeerUpdateValue(
+		return user->session().changes().peerFlagsValue(
 			user,
-			Notify::PeerUpdate::Flag::BotCommandsChanged
+			Data::PeerUpdate::Flag::BotCommands
 		) | rpl::map([=] {
 			return !findBotCommand(command).isEmpty();
 		});
@@ -597,10 +598,10 @@ void ActionsFiller::addReportAction() {
 void ActionsFiller::addBlockAction(not_null<UserData*> user) {
 	const auto window = &_controller->parentController()->window();
 
-	auto text = Notify::PeerUpdateValue(
+	auto text = user->session().changes().peerFlagsValue(
 		user,
-		Notify::PeerUpdate::Flag::UserIsBlocked
-	) | rpl::map([user] {
+		Data::PeerUpdate::Flag::IsBlocked
+	) | rpl::map([=] {
 		switch (user->blockStatus()) {
 		case UserData::BlockStatus::Blocked:
 			return ((user->isBot() && !user->isSupport())
diff --git a/Telegram/SourceFiles/info/profile/info_profile_cover.cpp b/Telegram/SourceFiles/info/profile/info_profile_cover.cpp
index 61f1d839a..ad7e4cd0a 100644
--- a/Telegram/SourceFiles/info/profile/info_profile_cover.cpp
+++ b/Telegram/SourceFiles/info/profile/info_profile_cover.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_peer_values.h"
 #include "data/data_channel.h"
 #include "data/data_chat.h"
+#include "data/data_changes.h"
 #include "info/profile/info_profile_values.h"
 #include "info/info_controller.h"
 #include "info/info_memento.h"
@@ -24,7 +25,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/unread_badge.h"
 #include "base/unixtime.h"
 #include "window/window_session_controller.h"
-#include "observer_peer.h"
 #include "core/application.h"
 #include "main/main_session.h"
 #include "apiwrap.h"
@@ -298,7 +298,7 @@ Cover *Cover::setOnlineCount(rpl::producer<int> &&count) {
 }
 
 void Cover::initViewers(rpl::producer<QString> title) {
-	using Flag = Notify::PeerUpdate::Flag;
+	using Flag = Data::PeerUpdate::Flag;
 	std::move(
 		title
 	) | rpl::start_with_next([=](const QString &title) {
@@ -306,16 +306,16 @@ void Cover::initViewers(rpl::producer<QString> title) {
 		refreshNameGeometry(width());
 	}, lifetime());
 
-	Notify::PeerUpdateValue(
+	_peer->session().changes().peerFlagsValue(
 		_peer,
-		Flag::UserOnlineChanged | Flag::MembersChanged
+		Flag::OnlineStatus | Flag::Members
 	) | rpl::start_with_next(
 		[=] { refreshStatusText(); },
 		lifetime());
 	if (!_peer->isUser()) {
-		Notify::PeerUpdateValue(
+		_peer->session().changes().peerFlagsValue(
 			_peer,
-			Flag::RightsChanged
+			Flag::Rights
 		) | rpl::start_with_next(
 			[=] { refreshUploadPhotoOverlay(); },
 			lifetime());
diff --git a/Telegram/SourceFiles/info/profile/info_profile_members_controllers.cpp b/Telegram/SourceFiles/info/profile/info_profile_members_controllers.cpp
index 5c243d304..0cbb70afc 100644
--- a/Telegram/SourceFiles/info/profile/info_profile_members_controllers.cpp
+++ b/Telegram/SourceFiles/info/profile/info_profile_members_controllers.cpp
@@ -15,7 +15,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "apiwrap.h"
 #include "main/main_session.h"
 #include "mainwidget.h"
-#include "observer_peer.h"
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
diff --git a/Telegram/SourceFiles/info/profile/info_profile_values.cpp b/Telegram/SourceFiles/info/profile/info_profile_values.cpp
index 19ff33713..9fdd180ef 100644
--- a/Telegram/SourceFiles/info/profile/info_profile_values.cpp
+++ b/Telegram/SourceFiles/info/profile/info_profile_values.cpp
@@ -7,7 +7,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "info/profile/info_profile_values.h"
 
-#include "observer_peer.h"
 #include "core/application.h"
 #include "main/main_session.h"
 #include "ui/wrap/slide_wrap.h"
@@ -16,6 +15,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_peer_values.h"
 #include "data/data_shared_media.h"
 #include "data/data_folder.h"
+#include "data/data_changes.h"
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
@@ -27,17 +27,21 @@ namespace Info {
 namespace Profile {
 namespace {
 
+using UpdateFlag = Data::PeerUpdate::Flag;
+
 auto PlainBioValue(not_null<UserData*> user) {
-	return Notify::PeerUpdateValue(
+	return user->session().changes().peerFlagsValue(
 		user,
-		Notify::PeerUpdate::Flag::AboutChanged
-	) | rpl::map([=] { return user->about(); });
+		UpdateFlag::About
+	) | rpl::map([=] {
+		return user->about();
+	});
 }
 
 auto PlainUsernameValue(not_null<PeerData*> peer) {
-	return Notify::PeerUpdateValue(
+	return peer->session().changes().peerFlagsValue(
 		peer,
-		Notify::PeerUpdate::Flag::UsernameChanged
+		UpdateFlag::Username
 	) | rpl::map([=] {
 		return peer->userName();
 	});
@@ -46,19 +50,19 @@ auto PlainUsernameValue(not_null<PeerData*> peer) {
 } // namespace
 
 rpl::producer<TextWithEntities> NameValue(not_null<PeerData*> peer) {
-	return Notify::PeerUpdateValue(
+	return peer->session().changes().peerFlagsValue(
 		peer,
-		Notify::PeerUpdate::Flag::NameChanged
+		UpdateFlag::Name
 	) | rpl::map([=] {
 		return peer->name;
-	}) | Ui::Text::ToWithEntities();
+	}) | Ui::Text::ToWithEntities();;
 }
 
 rpl::producer<TextWithEntities> PhoneValue(not_null<UserData*> user) {
-	return Notify::PeerUpdateValue(
-			user,
-			Notify::PeerUpdate::Flag::UserPhoneChanged
-	) | rpl::map([user] {
+	return user->session().changes().peerFlagsValue(
+		user,
+		UpdateFlag::PhoneNumber
+	) | rpl::map([=] {
 		return App::formatPhone(user->phone());
 	}) | Ui::Text::ToWithEntities();
 }
@@ -102,10 +106,12 @@ rpl::producer<QString> PlainAboutValue(not_null<PeerData*> peer) {
 			return rpl::single(QString());
 		}
 	}
-	return Notify::PeerUpdateValue(
+	return peer->session().changes().peerFlagsValue(
 		peer,
-		Notify::PeerUpdate::Flag::AboutChanged
-	) | rpl::map([=] { return peer->about(); });
+		UpdateFlag::About
+	) | rpl::map([=] {
+		return peer->about();
+	});
 }
 
 rpl::producer<TextWithEntities> AboutValue(not_null<PeerData*> peer) {
@@ -136,9 +142,9 @@ rpl::producer<QString> LinkValue(not_null<PeerData*> peer) {
 
 rpl::producer<const ChannelLocation*> LocationValue(
 		not_null<ChannelData*> channel) {
-	return Notify::PeerUpdateValue(
+	return channel->session().changes().peerFlagsValue(
 		channel,
-		Notify::PeerUpdate::Flag::ChannelLocation
+		UpdateFlag::ChannelLocation
 	) | rpl::map([=] {
 		return channel->getLocation();
 	});
@@ -146,9 +152,9 @@ rpl::producer<const ChannelLocation*> LocationValue(
 
 rpl::producer<bool> NotificationsEnabledValue(not_null<PeerData*> peer) {
 	return rpl::merge(
-		Notify::PeerUpdateValue(
+		peer->session().changes().peerFlagsValue(
 			peer,
-			Notify::PeerUpdate::Flag::NotificationsEnabled
+			UpdateFlag::Notifications
 		) | rpl::map([] { return rpl::empty_value(); }),
 		peer->owner().defaultNotifyUpdates(peer)
 	) | rpl::map([=] {
@@ -157,29 +163,31 @@ rpl::producer<bool> NotificationsEnabledValue(not_null<PeerData*> peer) {
 }
 
 rpl::producer<bool> IsContactValue(not_null<UserData*> user) {
-	return Notify::PeerUpdateValue(
-			user,
-			Notify::PeerUpdate::Flag::UserIsContact
-	) | rpl::map([user] { return user->isContact(); });
+	return user->session().changes().peerFlagsValue(
+		user,
+		UpdateFlag::IsContact
+	) | rpl::map([=] {
+		return user->isContact();
+	});
 }
 
 rpl::producer<bool> CanInviteBotToGroupValue(not_null<UserData*> user) {
 	if (!user->isBot() || user->isSupport()) {
 		return rpl::single(false);
 	}
-	return Notify::PeerUpdateValue(
-			user,
-			Notify::PeerUpdate::Flag::BotCanAddToGroups
-	) | rpl::map([user] {
+	return user->session().changes().peerFlagsValue(
+		user,
+		UpdateFlag::BotCanBeInvited
+	) | rpl::map([=] {
 		return !user->botInfo->cantJoinGroups;
 	});
 }
 
 rpl::producer<bool> CanShareContactValue(not_null<UserData*> user) {
-	return Notify::PeerUpdateValue(
-			user,
-			Notify::PeerUpdate::Flag::UserCanShareContact
-	) | rpl::map([user] {
+	return user->session().changes().peerFlagsValue(
+		user,
+		UpdateFlag::CanShareContact
+	) | rpl::map([=] {
 		return user->canShareThisContact();
 	});
 }
@@ -195,28 +203,29 @@ rpl::producer<bool> CanAddContactValue(not_null<UserData*> user) {
 }
 
 rpl::producer<bool> AmInChannelValue(not_null<ChannelData*> channel) {
-	return Notify::PeerUpdateValue(
+	return channel->session().changes().peerFlagsValue(
 		channel,
-		Notify::PeerUpdate::Flag::ChannelAmIn
-	) | rpl::map([channel] { return channel->amIn(); });
+		UpdateFlag::ChannelAmIn
+	) | rpl::map([=] {
+		return channel->amIn();
+	});
 }
 
 rpl::producer<int> MembersCountValue(not_null<PeerData*> peer) {
-	using Flag = Notify::PeerUpdate::Flag;
 	if (const auto chat = peer->asChat()) {
-		return Notify::PeerUpdateValue(
+		return peer->session().changes().peerFlagsValue(
 			peer,
-			Flag::MembersChanged
-		) | rpl::map([chat] {
+			UpdateFlag::Members
+		) | rpl::map([=] {
 			return chat->amIn()
 				? std::max(chat->count, int(chat->participants.size()))
 				: 0;
 		});
 	} else if (const auto channel = peer->asChannel()) {
-		return Notify::PeerUpdateValue(
-			channel,
-			Flag::MembersChanged
-		) | rpl::map([channel] {
+		return peer->session().changes().peerFlagsValue(
+			peer,
+			UpdateFlag::Members
+		) | rpl::map([=] {
 			return channel->membersCount();
 		});
 	}
@@ -224,20 +233,19 @@ rpl::producer<int> MembersCountValue(not_null<PeerData*> peer) {
 }
 
 rpl::producer<int> AdminsCountValue(not_null<PeerData*> peer) {
-	using Flag = Notify::PeerUpdate::Flag;
 	if (const auto chat = peer->asChat()) {
-		return Notify::PeerUpdateValue(
-			chat,
-			Flag::AdminsChanged | Flag::RightsChanged
+		return peer->session().changes().peerFlagsValue(
+			peer,
+			UpdateFlag::Admins | UpdateFlag::Rights
 		) | rpl::map([=] {
 			return chat->participants.empty()
 				? 0
 				: int(chat->admins.size() + 1); // + creator
 		});
 	} else if (const auto channel = peer->asChannel()) {
-		return Notify::PeerUpdateValue(
-			channel,
-			Flag::AdminsChanged | Flag::RightsChanged
+		return peer->session().changes().peerFlagsValue(
+			peer,
+			UpdateFlag::Admins | UpdateFlag::Rights
 		) | rpl::map([=] {
 			return channel->canViewAdmins()
 				? channel->adminsCount()
@@ -257,18 +265,17 @@ rpl::producer<int> RestrictionsCountValue(not_null<PeerData*> peer) {
 		return int(Data::ListOfRestrictions().size()) - count;
 	};
 
-	using Flag = Notify::PeerUpdate::Flag;
 	if (const auto chat = peer->asChat()) {
-		return Notify::PeerUpdateValue(
-			chat,
-			Flag::RightsChanged
+		return peer->session().changes().peerFlagsValue(
+			peer,
+			UpdateFlag::Rights
 		) | rpl::map([=] {
 			return countOfRestrictions(chat->defaultRestrictions());
 		});
 	} else if (const auto channel = peer->asChannel()) {
-		return Notify::PeerUpdateValue(
-			channel,
-			Flag::RightsChanged
+		return peer->session().changes().peerFlagsValue(
+			peer,
+			UpdateFlag::Rights
 		) | rpl::map([=] {
 			return countOfRestrictions(channel->defaultRestrictions());
 		});
@@ -278,11 +285,10 @@ rpl::producer<int> RestrictionsCountValue(not_null<PeerData*> peer) {
 
 rpl::producer<not_null<PeerData*>> MigratedOrMeValue(
 		not_null<PeerData*> peer) {
-	using Flag = Notify::PeerUpdate::Flag;
 	if (const auto chat = peer->asChat()) {
-		return Notify::PeerUpdateValue(
-			chat,
-			Flag::MigrationChanged
+		return peer->session().changes().peerFlagsValue(
+			peer,
+			UpdateFlag::Migration
 		) | rpl::map([=] {
 			return chat->migrateToOrMe();
 		});
@@ -292,10 +298,9 @@ rpl::producer<not_null<PeerData*>> MigratedOrMeValue(
 }
 
 rpl::producer<int> RestrictedCountValue(not_null<ChannelData*> channel) {
-	using Flag = Notify::PeerUpdate::Flag;
-	return Notify::PeerUpdateValue(
+	return channel->session().changes().peerFlagsValue(
 		channel,
-		Flag::BannedUsersChanged | Flag::RightsChanged
+		UpdateFlag::BannedUsers | UpdateFlag::Rights
 	) | rpl::map([=] {
 		return channel->canViewBanned()
 			? channel->restrictedCount()
@@ -304,10 +309,9 @@ rpl::producer<int> RestrictedCountValue(not_null<ChannelData*> channel) {
 }
 
 rpl::producer<int> KickedCountValue(not_null<ChannelData*> channel) {
-	using Flag = Notify::PeerUpdate::Flag;
-	return Notify::PeerUpdateValue(
+	return channel->session().changes().peerFlagsValue(
 		channel,
-		Flag::BannedUsersChanged | Flag::RightsChanged
+		UpdateFlag::BannedUsers | UpdateFlag::Rights
 	) | rpl::map([=] {
 		return channel->canViewBanned()
 			? channel->kickedCount()
@@ -338,26 +342,26 @@ rpl::producer<int> SharedMediaCountValue(
 }
 
 rpl::producer<int> CommonGroupsCountValue(not_null<UserData*> user) {
-	return Notify::PeerUpdateValue(
+	return user->session().changes().peerFlagsValue(
 		user,
-		Notify::PeerUpdate::Flag::UserCommonChatsChanged
-	) | rpl::map([user] {
+		UpdateFlag::CommonChats
+	) | rpl::map([=] {
 		return user->commonChatsCount();
 	});
 }
 
 rpl::producer<bool> CanAddMemberValue(not_null<PeerData*> peer) {
 	if (const auto chat = peer->asChat()) {
-		return Notify::PeerUpdateValue(
-			chat,
-			Notify::PeerUpdate::Flag::RightsChanged
+		return peer->session().changes().peerFlagsValue(
+			peer,
+			UpdateFlag::Rights
 		) | rpl::map([=] {
 			return chat->canAddMembers();
 		});
 	} else if (const auto channel = peer->asChannel()) {
-		return Notify::PeerUpdateValue(
-			channel,
-			Notify::PeerUpdate::Flag::RightsChanged
+		return peer->session().changes().peerFlagsValue(
+			peer,
+			UpdateFlag::Rights
 		) | rpl::map([=] {
 			return channel->canAddMembers();
 		});
diff --git a/Telegram/SourceFiles/info/profile/info_profile_values.h b/Telegram/SourceFiles/info/profile/info_profile_values.h
index 39bd89d83..2601d690d 100644
--- a/Telegram/SourceFiles/info/profile/info_profile_values.h
+++ b/Telegram/SourceFiles/info/profile/info_profile_values.h
@@ -9,7 +9,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include <rpl/producer.h>
 #include <rpl/map.h>
-#include "observer_peer.h"
 
 struct ChannelLocation;
 
diff --git a/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp b/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
index 225b5f471..5c865404b 100644
--- a/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
+++ b/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_user.h"
 #include "data/data_session.h"
 #include "data/data_file_origin.h"
+#include "data/data_changes.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/shadow.h"
 #include "ui/effects/ripple_animation.h"
@@ -29,7 +30,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "window/window_session_controller.h"
 #include "ui/widgets/scroll_area.h"
 #include "ui/widgets/labels.h"
-#include "observer_peer.h"
 #include "history/view/history_view_cursor_state.h"
 #include "facades.h"
 #include "app.h"
@@ -49,7 +49,7 @@ constexpr auto kInlineBotRequestDelay = 400;
 Inner::Inner(
 	QWidget *parent,
 	not_null<Window::SessionController*> controller)
-: TWidget(parent)
+: RpWidget(parent)
 , _controller(controller)
 , _updateInlineItems([=] { updateInlineItems(); })
 , _previewTimer([=] { showPreview(); }) {
@@ -66,15 +66,18 @@ Inner::Inner(
 			update();
 		}
 	});
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::RightsChanged, [this](const Notify::PeerUpdate &update) {
-		if (update.peer == _inlineQueryPeer) {
-			auto isRestricted = (_restrictedLabel != nullptr);
-			if (isRestricted != isRestrictedView()) {
-				auto h = countHeight();
-				if (h != height()) resize(width(), h);
-			}
+
+	_controller->session().changes().peerUpdates(
+		Data::PeerUpdate::Flag::Rights
+	) | rpl::filter([=](const Data::PeerUpdate &update) {
+		return (update.peer.get() == _inlineQueryPeer);
+	}) | rpl::start_with_next([=] {
+		auto isRestricted = (_restrictedLabel != nullptr);
+		if (isRestricted != isRestrictedView()) {
+			auto h = countHeight();
+			if (h != height()) resize(width(), h);
 		}
-	}));
+	}, lifetime());
 }
 
 void Inner::visibleTopBottomUpdated(
diff --git a/Telegram/SourceFiles/inline_bots/inline_results_widget.h b/Telegram/SourceFiles/inline_bots/inline_results_widget.h
index c2e93dbe3..a86cda86a 100644
--- a/Telegram/SourceFiles/inline_bots/inline_results_widget.h
+++ b/Telegram/SourceFiles/inline_bots/inline_results_widget.h
@@ -25,7 +25,7 @@ class LinkButton;
 class RoundButton;
 class FlatLabel;
 class RippleAnimation;
-} // namesapce Ui
+} // namespace Ui
 
 namespace Window {
 class SessionController;
@@ -52,7 +52,7 @@ struct CacheEntry {
 };
 
 class Inner
-	: public TWidget
+	: public Ui::RpWidget
 	, public Ui::AbstractTooltipShower
 	, public Context
 	, private base::Subscriber {
diff --git a/Telegram/SourceFiles/main/main_account.cpp b/Telegram/SourceFiles/main/main_account.cpp
index 73a70fdf3..3fa341200 100644
--- a/Telegram/SourceFiles/main/main_account.cpp
+++ b/Telegram/SourceFiles/main/main_account.cpp
@@ -15,11 +15,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/localstorage.h"
 #include "data/data_session.h"
 #include "data/data_user.h"
+#include "data/data_changes.h"
 #include "window/window_controller.h"
 #include "media/audio/media_audio.h"
 #include "ui/image/image.h"
 #include "mainwidget.h"
-#include "observer_peer.h"
 #include "api/api_updates.h"
 #include "main/main_app_config.h"
 #include "main/main_session.h"
@@ -377,7 +377,7 @@ void Account::startMtp() {
 
 	if (sessionExists()) {
 		// Skip all pending self updates so that we won't local().writeSelf.
-		Notify::peerUpdatedSendDelayed();
+		session().changes().sendNotifications();
 	}
 
 	_mtpValue = _mtp.get();
diff --git a/Telegram/SourceFiles/main/main_session.cpp b/Telegram/SourceFiles/main/main_session.cpp
index 82295708e..3e77a141a 100644
--- a/Telegram/SourceFiles/main/main_session.cpp
+++ b/Telegram/SourceFiles/main/main_session.cpp
@@ -21,6 +21,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/storage_facade.h"
 #include "storage/storage_account.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "data/data_user.h"
 #include "window/notifications_manager.h"
 #include "window/window_session_controller.h"
@@ -28,7 +29,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 //#include "platform/platform_specific.h"
 #include "calls/calls_instance.h"
 #include "support/support_helper.h"
-#include "observer_peer.h"
 #include "facades.h"
 
 #ifndef TDESKTOP_DISABLE_SPELLCHECK
@@ -56,6 +56,7 @@ Session::Session(
 , _uploader(std::make_unique<Storage::Uploader>(_api.get()))
 , _storage(std::make_unique<Storage::Facade>())
 , _notifications(std::make_unique<Window::Notifications::System>(this))
+, _changes(std::make_unique<Data::Changes>(this))
 , _data(std::make_unique<Data::Session>(this))
 , _user(_data->processUser(user))
 , _emojiStickersPack(std::make_unique<Stickers::EmojiPack>(this))
@@ -74,21 +75,17 @@ Session::Session(
 	_api->requestFullPeer(_user);
 
 	crl::on_main(this, [=] {
-		using Flag = Notify::PeerUpdate::Flag;
-		const auto events = Flag::NameChanged
-			| Flag::UsernameChanged
-			| Flag::PhotoChanged
-			| Flag::AboutChanged
-			| Flag::UserPhoneChanged;
-		subscribe(
-			Notify::PeerUpdated(),
-			Notify::PeerUpdatedHandler(
-				events,
-				[=](const Notify::PeerUpdate &update) {
-					if (update.peer == _user) {
-						local().writeSelf();
-					}
-				}));
+		using Flag = Data::PeerUpdate::Flag;
+		changes().peerUpdates(
+			_user,
+			Flag::Name
+			| Flag::Username
+			| Flag::Photo
+			| Flag::About
+			| Flag::PhoneNumber
+		) | rpl::start_with_next([=] {
+			local().writeSelf();
+		}, _lifetime);
 
 		if (_settings.hadLegacyCallsPeerToPeerNobody()) {
 			api().savePrivacy(
diff --git a/Telegram/SourceFiles/main/main_session.h b/Telegram/SourceFiles/main/main_session.h
index bb71e4998..710e071f8 100644
--- a/Telegram/SourceFiles/main/main_session.h
+++ b/Telegram/SourceFiles/main/main_session.h
@@ -30,6 +30,7 @@ class Templates;
 
 namespace Data {
 class Session;
+class Changes;
 } // namespace Data
 
 namespace Storage {
@@ -104,11 +105,12 @@ public:
 	[[nodiscard]] Stickers::DicePacks &diceStickersPacks() const {
 		return *_diceStickersPacks;
 	}
-
 	[[nodiscard]] Window::Notifications::System &notifications() {
 		return *_notifications;
 	}
-
+	[[nodiscard]] Data::Changes &changes() {
+		return *_changes;
+	}
 	[[nodiscard]] Data::Session &data() {
 		return *_data;
 	}
@@ -164,6 +166,7 @@ private:
 	const std::unique_ptr<Window::Notifications::System> _notifications;
 
 	// _data depends on _downloader / _uploader / _notifications.
+	const std::unique_ptr<Data::Changes> _changes;
 	const std::unique_ptr<Data::Session> _data;
 	const not_null<UserData*> _user;
 
diff --git a/Telegram/SourceFiles/mainwidget.cpp b/Telegram/SourceFiles/mainwidget.cpp
index 44f0e04db..13e4a01de 100644
--- a/Telegram/SourceFiles/mainwidget.cpp
+++ b/Telegram/SourceFiles/mainwidget.cpp
@@ -47,7 +47,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "chat_helpers/message_field.h"
 #include "info/info_memento.h"
 #include "info/info_controller.h"
-#include "observer_peer.h"
 #include "apiwrap.h"
 #include "dialogs/dialogs_widget.h"
 #include "dialogs/dialogs_key.h"
@@ -241,9 +240,9 @@ MainWidget::MainWidget(
 	}, lifetime());
 
 	// Load current userpic and keep it loaded.
-	Notify::PeerUpdateValue(
+	session().changes().peerFlagsValue(
 		session().user(),
-		Notify::PeerUpdate::Flag::PhotoChanged
+		Data::PeerUpdate::Flag::Photo
 	) | rpl::start_with_next([=] {
 		[[maybe_unused]] const auto image = session().user()->currentUserpic(
 			_selfUserpicView);
@@ -253,7 +252,6 @@ MainWidget::MainWidget(
 	setupConnectingWidget();
 
 	connect(_dialogs, SIGNAL(cancelled()), this, SLOT(dialogsCancelled()));
-	connect(this, SIGNAL(dialogsUpdated()), _dialogs, SLOT(onListScroll()));
 	connect(_history, &HistoryWidget::cancelled, [=] { handleHistoryBack(); });
 
 	Media::Player::instance()->updatedNotifier(
@@ -283,6 +281,16 @@ MainWidget::MainWidget(
 		[this] { updateControlsGeometry(); },
 		lifetime());
 
+	session().data().newMessageSent(
+	) | rpl::start_with_next([=](not_null<History*> history) {
+		history->forgetScrollState();
+		if (const auto from = history->peer->migrateFrom()) {
+			if (const auto migrated = history->owner().historyLoaded(from)) {
+				migrated->forgetScrollState();
+			}
+		}
+	}, lifetime());
+
 	// MSVC BUG + REGRESSION rpl::mappers::tuple :(
 	using namespace rpl::mappers;
 	_controller->activeChatValue(
@@ -542,29 +550,6 @@ bool MainWidget::inlineSwitchChosen(PeerId peerId, const QString &botAndQuery) {
 	return true;
 }
 
-void MainWidget::cancelForwarding(not_null<History*> history) {
-	history->setForwardDraft({});
-	_history->updateForwarding();
-}
-
-void MainWidget::finishForwarding(Api::SendAction action) {
-	const auto history = action.history;
-	auto toForward = history->validateForwardDraft();
-	if (!toForward.empty()) {
-		const auto error = GetErrorTextForSending(history->peer, toForward);
-		if (!error.isEmpty()) {
-			return;
-		}
-
-		session().api().forwardMessages(std::move(toForward), action);
-		cancelForwarding(history);
-	}
-
-	session().data().sendHistoryChangeNotifications();
-	historyToDown(history);
-	dialogsToUp();
-}
-
 bool MainWidget::sendPaths(PeerId peerId) {
 	Expects(peerId != 0);
 
@@ -1989,10 +1974,6 @@ void MainWidget::windowShown() {
 	_history->windowShown();
 }
 
-void MainWidget::historyToDown(History *history) {
-	_history->historyToDown(history);
-}
-
 void MainWidget::dialogsToUp() {
 	_dialogs->jumpToTop();
 }
@@ -2775,120 +2756,6 @@ void MainWidget::usernameResolveFail(const RPCError &error, const QString &usern
 	}
 }
 
-void MainWidget::incrementSticker(DocumentData *sticker) {
-	if (!sticker
-		|| !sticker->sticker()
-		|| sticker->sticker()->set.type() == mtpc_inputStickerSetEmpty) {
-		return;
-	}
-
-	bool writeRecentStickers = false;
-	auto &sets = session().data().stickers().setsRef();
-	auto it = sets.find(Data::Stickers::CloudRecentSetId);
-	if (it == sets.cend()) {
-		if (it == sets.cend()) {
-			it = sets.emplace(
-				Data::Stickers::CloudRecentSetId,
-				std::make_unique<Data::StickersSet>(
-					&session().data(),
-					Data::Stickers::CloudRecentSetId,
-					uint64(0),
-					tr::lng_recent_stickers(tr::now),
-					QString(),
-					0, // count
-					0, // hash
-					MTPDstickerSet_ClientFlag::f_special | 0,
-					TimeId(0))).first;
-		} else {
-			it->second->title = tr::lng_recent_stickers(tr::now);
-		}
-	}
-	const auto set = it->second.get();
-	auto removedFromEmoji = std::vector<not_null<EmojiPtr>>();
-	auto index = set->stickers.indexOf(sticker);
-	if (index > 0) {
-		if (set->dates.empty()) {
-			session().api().requestRecentStickersForce();
-		} else {
-			Assert(set->dates.size() == set->stickers.size());
-			set->dates.erase(set->dates.begin() + index);
-		}
-		set->stickers.removeAt(index);
-		for (auto i = set->emoji.begin(); i != set->emoji.end();) {
-			if (const auto index = i->indexOf(sticker); index >= 0) {
-				removedFromEmoji.emplace_back(i.key());
-				i->removeAt(index);
-				if (i->isEmpty()) {
-					i = set->emoji.erase(i);
-					continue;
-				}
-			}
-			++i;
-		}
-	}
-	if (index) {
-		if (set->dates.size() == set->stickers.size()) {
-			set->dates.insert(set->dates.begin(), base::unixtime::now());
-		}
-		set->stickers.push_front(sticker);
-		if (const auto emojiList = session().data().stickers().getEmojiListFromSet(sticker)) {
-			for (const auto emoji : *emojiList) {
-				set->emoji[emoji].push_front(sticker);
-			}
-		} else if (!removedFromEmoji.empty()) {
-			for (const auto emoji : removedFromEmoji) {
-				set->emoji[emoji].push_front(sticker);
-			}
-		} else {
-			session().api().requestRecentStickersForce();
-		}
-
-		writeRecentStickers = true;
-	}
-
-	// Remove that sticker from old recent, now it is in cloud recent stickers.
-	bool writeOldRecent = false;
-	auto &recent = session().data().stickers().getRecentPack();
-	for (auto i = recent.begin(), e = recent.end(); i != e; ++i) {
-		if (i->first == sticker) {
-			writeOldRecent = true;
-			recent.erase(i);
-			break;
-		}
-	}
-	while (!recent.isEmpty() && set->stickers.size() + recent.size() > Global::StickersRecentLimit()) {
-		writeOldRecent = true;
-		recent.pop_back();
-	}
-
-	if (writeOldRecent) {
-		session().local().writeSettings();
-	}
-
-	// Remove that sticker from custom stickers, now it is in cloud recent stickers.
-	bool writeInstalledStickers = false;
-	auto customIt = sets.find(Data::Stickers::CustomSetId);
-	if (customIt != sets.cend()) {
-		const auto custom = customIt->second.get();
-		int removeIndex = custom->stickers.indexOf(sticker);
-		if (removeIndex >= 0) {
-			custom->stickers.removeAt(removeIndex);
-			if (custom->stickers.isEmpty()) {
-				sets.erase(customIt);
-			}
-			writeInstalledStickers = true;
-		}
-	}
-
-	if (writeInstalledStickers) {
-		session().local().writeInstalledStickers();
-	}
-	if (writeRecentStickers) {
-		session().local().writeRecentStickers();
-	}
-	_controller->tabbedSelector()->refreshStickers();
-}
-
 void MainWidget::activate() {
 	if (_a_show.animating()) {
 		return;
diff --git a/Telegram/SourceFiles/mainwidget.h b/Telegram/SourceFiles/mainwidget.h
index e56b78b2a..75e58752a 100644
--- a/Telegram/SourceFiles/mainwidget.h
+++ b/Telegram/SourceFiles/mainwidget.h
@@ -32,10 +32,6 @@ namespace Main {
 class Session;
 } // namespace Main
 
-namespace Notify {
-struct PeerUpdate;
-} // namespace Notify
-
 namespace Data {
 class WallPaper;
 class CloudImageView;
@@ -131,9 +127,6 @@ public:
 		FullMsgId clickFromMessageId = FullMsgId());
 
 	bool started();
-
-	void incrementSticker(DocumentData *sticker);
-
 	void activate();
 
 	void refreshDialog(Dialogs::Key key);
@@ -144,7 +137,6 @@ public:
 
 	void windowShown();
 
-	void historyToDown(History *hist);
 	void dialogsToUp();
 	void checkHistoryActivation();
 
@@ -226,9 +218,6 @@ public:
 
 	void pushReplyReturn(not_null<HistoryItem*> item);
 
-	void cancelForwarding(not_null<History*> history);
-	void finishForwarding(Api::SendAction action);
-
 	// Does offerPeer or showPeerHistory.
 	void choosePeer(PeerId peerId, MsgId showAtMsgId);
 	void clearBotStartToken(PeerData *peer);
@@ -260,9 +249,6 @@ public:
 
 	void closeBothPlayers();
 
-signals:
-	void dialogsUpdated();
-
 public slots:
 	void inlineResultLoadProgress(FileLoader *loader);
 	void inlineResultLoadFailed(FileLoader *loader, bool started);
diff --git a/Telegram/SourceFiles/mainwindow.cpp b/Telegram/SourceFiles/mainwindow.cpp
index 097197b18..9bdf1abef 100644
--- a/Telegram/SourceFiles/mainwindow.cpp
+++ b/Telegram/SourceFiles/mainwindow.cpp
@@ -32,7 +32,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/confirm_box.h"
 #include "boxes/add_contact_box.h"
 #include "boxes/connection_box.h"
-#include "observer_peer.h"
 #include "storage/storage_account.h"
 #include "storage/localstorage.h"
 #include "apiwrap.h"
diff --git a/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp b/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
index 454888403..aa50b19c4 100644
--- a/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
+++ b/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
@@ -49,7 +49,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "main/main_account.h" // Account::sessionValue.
 #include "base/platform/base_platform_info.h"
 #include "base/unixtime.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "layout.h"
 #include "storage/file_download.h"
diff --git a/Telegram/SourceFiles/media/view/media_view_overlay_widget.h b/Telegram/SourceFiles/media/view/media_view_overlay_widget.h
index c9754106e..43491bccd 100644
--- a/Telegram/SourceFiles/media/view/media_view_overlay_widget.h
+++ b/Telegram/SourceFiles/media/view/media_view_overlay_widget.h
@@ -34,10 +34,6 @@ struct Preview;
 } // namespace Theme
 } // namespace Window
 
-namespace Notify {
-struct PeerUpdate;
-} // namespace Notify
-
 namespace Media {
 namespace Player {
 struct TrackState;
diff --git a/Telegram/SourceFiles/observer_peer.cpp b/Telegram/SourceFiles/observer_peer.cpp
deleted file mode 100644
index 158606cd1..000000000
--- a/Telegram/SourceFiles/observer_peer.cpp
+++ /dev/null
@@ -1,129 +0,0 @@
-/*
-This file is part of Telegram Desktop,
-the official desktop application for the Telegram messaging service.
-
-For license and copyright information please follow this link:
-https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
-*/
-#include "observer_peer.h"
-
-#include "base/observer.h"
-#include "facades.h"
-
-namespace Notify {
-namespace {
-
-using SmallUpdatesList = QVector<PeerUpdate>;
-NeverFreedPointer<SmallUpdatesList> SmallUpdates;
-using AllUpdatesList = QMap<PeerData*, PeerUpdate>;
-NeverFreedPointer<AllUpdatesList> AllUpdates;
-
-void StartCallback() {
-	SmallUpdates.createIfNull();
-	AllUpdates.createIfNull();
-}
-void FinishCallback() {
-	SmallUpdates.clear();
-	AllUpdates.clear();
-}
-
-base::Observable<PeerUpdate, PeerUpdatedHandler> PeerUpdatedObservable;
-
-} // namespace
-
-void mergePeerUpdate(PeerUpdate &mergeTo, const PeerUpdate &mergeFrom) {
-	if (!(mergeTo.flags & PeerUpdate::Flag::NameChanged)) {
-		if (mergeFrom.flags & PeerUpdate::Flag::NameChanged) {
-			mergeTo.oldNameFirstLetters = mergeFrom.oldNameFirstLetters;
-		}
-	}
-	mergeTo.flags |= mergeFrom.flags;
-}
-
-void peerUpdatedDelayed(const PeerUpdate &update) {
-	SmallUpdates.createIfNull();
-	AllUpdates.createIfNull();
-
-	Global::RefHandleDelayedPeerUpdates().call();
-
-	int existingUpdatesCount = SmallUpdates->size();
-	for (int i = 0; i < existingUpdatesCount; ++i) {
-		auto &existingUpdate = (*SmallUpdates)[i];
-		if (existingUpdate.peer == update.peer) {
-			mergePeerUpdate(existingUpdate, update);
-			return;
-		}
-	}
-
-	if (AllUpdates->isEmpty()) {
-		if (existingUpdatesCount < 5) {
-			SmallUpdates->push_back(update);
-		} else {
-			AllUpdates->insert(update.peer, update);
-		}
-	} else {
-		auto it = AllUpdates->find(update.peer);
-		if (it != AllUpdates->cend()) {
-			mergePeerUpdate(it.value(), update);
-			return;
-		}
-		AllUpdates->insert(update.peer, update);
-	}
-}
-
-void peerUpdatedSendDelayed() {
-	if (!SmallUpdates || !AllUpdates || SmallUpdates->empty()) return;
-
-	auto smallList = base::take(*SmallUpdates);
-	auto allList = base::take(*AllUpdates);
-	for (auto &update : smallList) {
-		PeerUpdated().notify(std::move(update), true);
-	}
-	for (auto &update : allList) {
-		PeerUpdated().notify(std::move(update), true);
-	}
-
-	if (SmallUpdates->isEmpty()) {
-		std::swap(smallList, *SmallUpdates);
-		SmallUpdates->resize(0);
-	}
-}
-
-base::Observable<PeerUpdate, PeerUpdatedHandler> &PeerUpdated() {
-	return PeerUpdatedObservable;
-}
-
-rpl::producer<PeerUpdate> PeerUpdateViewer(
-		PeerUpdate::Flags flags) {
-	return [=](const auto &consumer) {
-		auto lifetime = rpl::lifetime();
-		lifetime.make_state<base::Subscription>(
-			PeerUpdated().add_subscription({ flags, [=](
-					const PeerUpdate &update) {
-				consumer.put_next_copy(update);
-			}}));
-		return lifetime;
-	};
-}
-
-rpl::producer<PeerUpdate> PeerUpdateViewer(
-		not_null<PeerData*> peer,
-		PeerUpdate::Flags flags) {
-	return PeerUpdateViewer(
-		flags
-	) | rpl::filter([=](const PeerUpdate &update) {
-		return (update.peer == peer);
-	});
-}
-
-rpl::producer<PeerUpdate> PeerUpdateValue(
-		not_null<PeerData*> peer,
-		PeerUpdate::Flags flags) {
-	auto initial = PeerUpdate(peer);
-	initial.flags = flags;
-	return rpl::single(
-		initial
-	) | rpl::then(PeerUpdateViewer(peer, flags));
-}
-
-} // namespace Notify
diff --git a/Telegram/SourceFiles/observer_peer.h b/Telegram/SourceFiles/observer_peer.h
deleted file mode 100644
index ec5d7981d..000000000
--- a/Telegram/SourceFiles/observer_peer.h
+++ /dev/null
@@ -1,123 +0,0 @@
-/*
-This file is part of Telegram Desktop,
-the official desktop application for the Telegram messaging service.
-
-For license and copyright information please follow this link:
-https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
-*/
-#pragma once
-
-#include <rpl/producer.h>
-#include <rpl/filter.h>
-#include <rpl/then.h>
-#include <rpl/range.h>
-#include "base/observer.h"
-#include "base/flags.h"
-
-namespace Notify {
-
-// Generic notifications about updates of some PeerData.
-// You can subscribe to them by Notify::registerPeerObserver().
-// 0x0000FFFFU for general peer updates (valid for any peer).
-// 0xFFFF0000U for specific peer updates (valid for user / chat / channel).
-struct PeerUpdate {
-	PeerUpdate(PeerData *updated = nullptr) : peer(updated) {
-	}
-	PeerData *peer;
-
-	enum class Flag : uint32 {
-		None                      = 0,
-
-		// Common flags
-		NameChanged               = (1 << 0),
-		UsernameChanged           = (1 << 1),
-		PhotoChanged              = (1 << 2),
-		AboutChanged              = (1 << 3),
-		NotificationsEnabled      = (1 << 4),
-		MigrationChanged          = (1 << 6),
-		ChatPinnedChanged         = (1 << 7),
-		UnavailableReasonChanged  = (1 << 8),
-		UnreadViewChanged         = (1 << 9),
-		PinnedMessageChanged      = (1 << 10),
-		TopPromotedChanged        = (1 << 11),
-		FolderChanged             = (1 << 12),
-
-		// For chats and channels
-		InviteLinkChanged         = (1 << 13),
-		MembersChanged            = (1 << 14),
-		AdminsChanged             = (1 << 15),
-		BannedUsersChanged        = (1 << 16),
-		UnreadMentionsChanged     = (1 << 17),
-		RightsChanged             = (1 << 18),
-
-		// For users
-		UserCanShareContact       = (1 << 19),
-		UserIsContact             = (1 << 20),
-		UserPhoneChanged          = (1 << 21),
-		UserIsBlocked             = (1 << 22),
-		BotCommandsChanged        = (1 << 23),
-		UserOnlineChanged         = (1 << 24),
-		BotCanAddToGroups         = (1 << 25),
-		UserCommonChatsChanged    = (1 << 26),
-		UserHasCalls              = (1 << 27),
-		UserOccupiedChanged       = (1 << 28),
-		UserSupportInfoChanged    = (1 << 29),
-		UserIsBotChanged          = (1 << 30),
-
-		// For channels
-		ChannelAmIn               = (1 << 19),
-		ChannelStickersChanged    = (1 << 20),
-		ChannelPromotedChanged    = (1 << 21),
-		ChannelLinkedChat         = (1 << 22),
-		ChannelLocation           = (1 << 23),
-		ChannelSlowmode           = (1 << 24),
-		ChannelLocalMessages      = (1 << 25),
-	};
-	using Flags = base::flags<Flag>;
-	friend inline constexpr auto is_flag_type(Flag) { return true; }
-
-	Flags flags = 0;
-
-	// NameChanged data
-	base::flat_set<QChar> oldNameFirstLetters;
-
-};
-
-void peerUpdatedDelayed(const PeerUpdate &update);
-inline void peerUpdatedDelayed(PeerData *peer, PeerUpdate::Flags events) {
-	PeerUpdate update(peer);
-	update.flags = events;
-	peerUpdatedDelayed(update);
-}
-void peerUpdatedSendDelayed();
-
-class PeerUpdatedHandler {
-public:
-	template <typename Lambda>
-	PeerUpdatedHandler(PeerUpdate::Flags events, Lambda &&handler) : _events(events), _handler(std::move(handler)) {
-	}
-	void operator()(const PeerUpdate &update) const {
-		if (update.flags & _events) {
-			_handler(update);
-		}
-	}
-
-private:
-	PeerUpdate::Flags _events;
-	Fn<void(const PeerUpdate&)> _handler;
-
-};
-base::Observable<PeerUpdate, PeerUpdatedHandler> &PeerUpdated();
-
-rpl::producer<PeerUpdate> PeerUpdateViewer(
-	PeerUpdate::Flags flags);
-
-rpl::producer<PeerUpdate> PeerUpdateViewer(
-	not_null<PeerData*> peer,
-	PeerUpdate::Flags flags);
-
-rpl::producer<PeerUpdate> PeerUpdateValue(
-	not_null<PeerData*> peer,
-	PeerUpdate::Flags flags);
-
-} // namespace Notify
diff --git a/Telegram/SourceFiles/platform/mac/mac_touchbar.mm b/Telegram/SourceFiles/platform/mac/mac_touchbar.mm
index e6cb2017f..32912d538 100644
--- a/Telegram/SourceFiles/platform/mac/mac_touchbar.mm
+++ b/Telegram/SourceFiles/platform/mac/mac_touchbar.mm
@@ -21,6 +21,7 @@
 #include "data/data_file_origin.h"
 #include "data/data_folder.h"
 #include "data/data_peer_values.h"
+#include "data/data_changes.h"
 #include "data/data_session.h"
 #include "data/data_cloud_file.h"
 #include "data/stickers/data_stickers.h"
@@ -30,7 +31,6 @@
 #include "lang/lang_keys.h"
 #include "mainwidget.h"
 #include "mainwindow.h"
-#include "observer_peer.h"
 #include "base/platform/mac/base_utilities_mac.h"
 #include "styles/style_dialogs.h"
 #include "styles/style_media_player.h"
@@ -576,24 +576,24 @@ void AppendEmojiPacks(
 		return;
 	}
 	_userpicView = _peer->createUserpicView();
-	Notify::PeerUpdateViewer(
+	_peer->session().changes().peerUpdates(
 		_peer,
-		Notify::PeerUpdate::Flag::PhotoChanged
+		Data::PeerUpdate::Flag::Photo
 	) | rpl::start_with_next([=] {
 		isWaitingUserpicLoad = true;
 		[self updateUserpic];
 	}, _peerChangedLifetime);
 
-	Notify::PeerUpdateViewer(
-		_peer,
-		Notify::PeerUpdate::Flag::UnreadViewChanged
+	_peer->session().changes().historyUpdates(
+		_peer->session().history(_peer),
+		Data::HistoryUpdate::Flag::UnreadView
 	) | rpl::start_with_next([=] {
 		[self updateBadge];
 	}, _peerChangedLifetime);
 
-	Notify::PeerUpdateViewer(
+	_peer->session().changes().peerUpdates(
 		_peer,
-		Notify::PeerUpdate::Flag::UserOnlineChanged
+		Data::PeerUpdate::Flag::OnlineStatus
 	) | rpl::filter([=] {
 		return UnreadCount(_peer) == 0;
 	}) | rpl::start_with_next([=] {
diff --git a/Telegram/SourceFiles/profile/profile_block_group_members.cpp b/Telegram/SourceFiles/profile/profile_block_group_members.cpp
index 836c3e630..a67c574af 100644
--- a/Telegram/SourceFiles/profile/profile_block_group_members.cpp
+++ b/Telegram/SourceFiles/profile/profile_block_group_members.cpp
@@ -18,9 +18,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
+#include "data/data_changes.h"
 #include "mainwidget.h"
 #include "apiwrap.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "lang/lang_keys.h"
 #include "facades.h"
@@ -28,7 +28,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 namespace Profile {
 namespace {
 
-using UpdateFlag = Notify::PeerUpdate::Flag;
+using UpdateFlag = Data::PeerUpdate::Flag;
 
 } // namespace
 
@@ -41,18 +41,19 @@ not_null<UserData*> GroupMembersWidget::Member::user() const {
 
 GroupMembersWidget::GroupMembersWidget(
 	QWidget *parent,
-	PeerData *peer,
+	not_null<PeerData*> peer,
 	const style::PeerListItem &st)
 : PeerListWidget(parent, peer, QString(), st, tr::lng_profile_kick(tr::now)) {
 	_updateOnlineTimer.setSingleShot(true);
 	connect(&_updateOnlineTimer, SIGNAL(timeout()), this, SLOT(onUpdateOnlineDisplay()));
 
-	auto observeEvents = UpdateFlag::AdminsChanged
-		| UpdateFlag::MembersChanged
-		| UpdateFlag::UserOnlineChanged;
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(observeEvents, [this](const Notify::PeerUpdate &update) {
+	peer->session().changes().peerUpdates(
+		UpdateFlag::Admins
+		| UpdateFlag::Members
+		| UpdateFlag::OnlineStatus
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
 		notifyPeerUpdated(update);
-	}));
+	}, lifetime());
 
 	setRemovedCallback([=](PeerData *selectedPeer) {
 		removePeer(selectedPeer);
@@ -104,9 +105,9 @@ void GroupMembersWidget::removePeer(PeerData *selectedPeer) {
 		crl::guard(&peer->session(), callback)));
 }
 
-void GroupMembersWidget::notifyPeerUpdated(const Notify::PeerUpdate &update) {
+void GroupMembersWidget::notifyPeerUpdated(const Data::PeerUpdate &update) {
 	if (update.peer != peer()) {
-		if (update.flags & UpdateFlag::UserOnlineChanged) {
+		if (update.flags & UpdateFlag::OnlineStatus) {
 			if (auto user = update.peer->asUser()) {
 				refreshUserOnline(user);
 			}
@@ -114,11 +115,11 @@ void GroupMembersWidget::notifyPeerUpdated(const Notify::PeerUpdate &update) {
 		return;
 	}
 
-	if (update.flags & UpdateFlag::MembersChanged) {
+	if (update.flags & UpdateFlag::Members) {
 		refreshMembers();
 		contentSizeUpdated();
 	}
-	if (update.flags & UpdateFlag::AdminsChanged) {
+	if (update.flags & UpdateFlag::Admins) {
 		if (const auto chat = peer()->asChat()) {
 			for (const auto item : items()) {
 				setItemFlags(getMember(item), chat);
diff --git a/Telegram/SourceFiles/profile/profile_block_group_members.h b/Telegram/SourceFiles/profile/profile_block_group_members.h
index d3ab35219..33006c3a1 100644
--- a/Telegram/SourceFiles/profile/profile_block_group_members.h
+++ b/Telegram/SourceFiles/profile/profile_block_group_members.h
@@ -15,9 +15,9 @@ namespace Ui {
 class FlatLabel;
 } // namespace Ui
 
-namespace Notify {
+namespace Data {
 struct PeerUpdate;
-} // namespace Notify
+} // namespace Data
 
 namespace Profile {
 
@@ -25,7 +25,10 @@ class GroupMembersWidget : public PeerListWidget {
 	Q_OBJECT
 
 public:
-	GroupMembersWidget(QWidget *parent, PeerData *peer, const style::PeerListItem &st);
+	GroupMembersWidget(
+		QWidget *parent, 
+		not_null<PeerData*> peer, 
+		const style::PeerListItem &st);
 
 	int onlineCount() const {
 		return _onlineCount;
@@ -41,7 +44,7 @@ private slots:
 
 private:
 	// Observed notifications.
-	void notifyPeerUpdated(const Notify::PeerUpdate &update);
+	void notifyPeerUpdated(const Data::PeerUpdate &update);
 
 	void removePeer(PeerData *selectedPeer);
 	void refreshMembers();
diff --git a/Telegram/SourceFiles/profile/profile_block_peer_list.h b/Telegram/SourceFiles/profile/profile_block_peer_list.h
index 0d03ce8f8..7ead3ab7a 100644
--- a/Telegram/SourceFiles/profile/profile_block_peer_list.h
+++ b/Telegram/SourceFiles/profile/profile_block_peer_list.h
@@ -18,10 +18,6 @@ class RippleAnimation;
 class PopupMenu;
 } // namespace Ui
 
-namespace Notify {
-struct PeerUpdate;
-} // namespace Notify
-
 namespace style {
 struct PeerListItem;
 } // namespace style
diff --git a/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp b/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
index 93aa24c59..d946cb66c 100644
--- a/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
+++ b/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
@@ -10,11 +10,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "settings/settings_common.h"
 #include "lang/lang_keys.h"
 #include "apiwrap.h"
-#include "observer_peer.h"
 #include "mainwidget.h"
 #include "main/main_session.h"
 #include "data/data_user.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "history/admin_log/history_admin_log_item.h"
 #include "history/view/history_view_element.h"
 #include "history/view/history_view_message.h"
@@ -86,14 +86,16 @@ Main::Session &BlockUserBoxController::session() const {
 
 void BlockUserBoxController::prepareViewHook() {
 	delegate()->peerListSetTitle(tr::lng_blocked_list_add_title());
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::UserIsBlocked, [this](const Notify::PeerUpdate &update) {
-		if (auto user = update.peer->asUser()) {
+	session().changes().peerUpdates(
+		Data::PeerUpdate::Flag::IsBlocked
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
+		if (const auto user = update.peer->asUser()) {
 			if (auto row = delegate()->peerListFindRow(user->id)) {
 				updateIsBlocked(row, user);
 				delegate()->peerListUpdateRow(row);
 			}
 		}
-	}));
+	}, lifetime());
 }
 
 void BlockUserBoxController::updateIsBlocked(not_null<PeerListRow*> row, UserData *user) const {
@@ -192,11 +194,13 @@ void BlockedBoxController::prepare() {
 	setDescriptionText(tr::lng_contacts_loading(tr::now));
 	delegate()->peerListRefreshRows();
 
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::UserIsBlocked, [this](const Notify::PeerUpdate &update) {
+	session().changes().peerUpdates(
+		Data::PeerUpdate::Flag::IsBlocked
+	) | rpl::start_with_next([=](const Data::PeerUpdate &update) {
 		if (const auto user = update.peer->asUser()) {
 			handleBlockedEvent(user);
 		}
-	}));
+	}, lifetime());
 
 	_loadRequestId = -1;
 	_window->session().api().blockedUsersSlice(
diff --git a/Telegram/SourceFiles/support/support_helper.cpp b/Telegram/SourceFiles/support/support_helper.cpp
index d79a5ef23..174257a39 100644
--- a/Telegram/SourceFiles/support/support_helper.cpp
+++ b/Telegram/SourceFiles/support/support_helper.cpp
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_drafts.h"
 #include "data/data_user.h"
 #include "data/data_session.h"
+#include "data/data_changes.h"
 #include "api/api_text_entities.h"
 #include "history/history.h"
 #include "boxes/abstract_box.h"
@@ -27,7 +28,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/localimageloader.h"
 #include "core/sandbox.h"
 #include "main/main_session.h"
-#include "observer_peer.h"
 #include "apiwrap.h"
 #include "facades.h"
 #include "styles/style_layers.h"
@@ -334,14 +334,14 @@ void Helper::cloudDraftChanged(not_null<History*> history) {
 void Helper::chatOccupiedUpdated(not_null<History*> history) {
 	if (const auto till = OccupiedBySomeoneTill(history)) {
 		_occupiedChats[history] = till + 2;
-		Notify::peerUpdatedDelayed(
-			history->peer,
-			Notify::PeerUpdate::Flag::UserOccupiedChanged);
+		history->session().changes().historyUpdated(
+			history,
+			Data::HistoryUpdate::Flag::ChatOccupied);
 		checkOccupiedChats();
 	} else if (_occupiedChats.take(history)) {
-		Notify::peerUpdatedDelayed(
-			history->peer,
-			Notify::PeerUpdate::Flag::UserOccupiedChanged);
+		history->session().changes().historyUpdated(
+			history,
+			Data::HistoryUpdate::Flag::ChatOccupied);
 	}
 }
 
@@ -355,9 +355,9 @@ void Helper::checkOccupiedChats() {
 		if (nearest->second <= now) {
 			const auto history = nearest->first;
 			_occupiedChats.erase(nearest);
-			Notify::peerUpdatedDelayed(
-				history->peer,
-				Notify::PeerUpdate::Flag::UserOccupiedChanged);
+			history->session().changes().historyUpdated(
+				history,
+				Data::HistoryUpdate::Flag::ChatOccupied);
 		} else {
 			_checkOccupiedTimer.callOnce(
 				(nearest->second - now) * crl::time(1000));
@@ -440,9 +440,9 @@ void Helper::applyInfo(
 		not_null<UserData*> user,
 		const MTPhelp_UserInfo &result) {
 	const auto notify = [&] {
-		Notify::peerUpdatedDelayed(
+		user->session().changes().peerUpdated(
 			user,
-			Notify::PeerUpdate::Flag::UserSupportInfoChanged);
+			Data::PeerUpdate::Flag::SupportInfo);
 	};
 	const auto remove = [&] {
 		if (_userInformation.take(user)) {
@@ -468,9 +468,9 @@ void Helper::applyInfo(
 }
 
 rpl::producer<UserInfo> Helper::infoValue(not_null<UserData*> user) const {
-	return Notify::PeerUpdateValue(
+	return user->session().changes().peerFlagsValue(
 		user,
-		Notify::PeerUpdate::Flag::UserSupportInfoChanged
+		Data::PeerUpdate::Flag::SupportInfo
 	) | rpl::map([=] {
 		return infoCurrent(user);
 	});
diff --git a/Telegram/SourceFiles/ui/special_buttons.cpp b/Telegram/SourceFiles/ui/special_buttons.cpp
index cd98e6ca3..95761541d 100644
--- a/Telegram/SourceFiles/ui/special_buttons.cpp
+++ b/Telegram/SourceFiles/ui/special_buttons.cpp
@@ -20,6 +20,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_folder.h"
 #include "data/data_channel.h"
 #include "data/data_cloud_file.h"
+#include "data/data_changes.h"
 #include "history/history.h"
 #include "core/file_utilities.h"
 #include "core/application.h"
@@ -30,7 +31,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "main/main_session.h"
 #include "apiwrap.h"
 #include "mainwidget.h"
-#include "observer_peer.h"
 #include "facades.h"
 #include "app.h"
 
@@ -631,9 +631,9 @@ void UserpicButton::openPeerPhoto() {
 }
 
 void UserpicButton::setupPeerViewers() {
-	Notify::PeerUpdateViewer(
+	_peer->session().changes().peerUpdates(
 		_peer,
-		Notify::PeerUpdate::Flag::PhotoChanged
+		Data::PeerUpdate::Flag::Photo
 	) | rpl::start_with_next([=] {
 		processNewPeerPhoto();
 		update();
@@ -653,6 +653,7 @@ void UserpicButton::setupPeerViewers() {
 
 void UserpicButton::paintEvent(QPaintEvent *e) {
 	Painter p(this);
+
 	if (!_waiting && _notShownYet) {
 		_notShownYet = false;
 		startAnimation();
diff --git a/Telegram/SourceFiles/window/window_main_menu.cpp b/Telegram/SourceFiles/window/window_main_menu.cpp
index 28d1b646c..1d8cbe634 100644
--- a/Telegram/SourceFiles/window/window_main_menu.cpp
+++ b/Telegram/SourceFiles/window/window_main_menu.cpp
@@ -27,11 +27,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "calls/calls_box_controller.h"
 #include "lang/lang_keys.h"
 #include "core/click_handler_types.h"
-#include "observer_peer.h"
 #include "main/main_session.h"
 #include "data/data_folder.h"
 #include "data/data_session.h"
 #include "data/data_user.h"
+#include "data/data_changes.h"
 #include "mainwidget.h"
 #include "facades.h"
 #include "app.h"
@@ -213,11 +213,14 @@ MainMenu::MainMenu(
 	_version->setLink(2, std::make_shared<LambdaClickHandler>([] { Ui::show(Box<AboutBox>()); }));
 
 	subscribe(_controller->session().downloaderTaskFinished(), [=] { update(); });
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::UserPhoneChanged, [this](const Notify::PeerUpdate &update) {
-		if (update.peer->isSelf()) {
-			updatePhone();
-		}
-	}));
+
+	_controller->session().changes().peerUpdates(
+		_controller->session().user(),
+		Data::PeerUpdate::Flag::PhoneNumber
+	) | rpl::start_with_next([=] {
+		updatePhone();
+	}, lifetime());
+
 	subscribe(Global::RefPhoneCallsEnabledChanged(), [this] { refreshMenu(); });
 	subscribe(Window::Theme::Background(), [this](const Window::Theme::BackgroundUpdate &update) {
 		if (update.type == Window::Theme::BackgroundUpdate::Type::ApplyingTheme) {
diff --git a/Telegram/SourceFiles/window/window_peer_menu.cpp b/Telegram/SourceFiles/window/window_peer_menu.cpp
index 62ba85845..f6c10bbc8 100644
--- a/Telegram/SourceFiles/window/window_peer_menu.cpp
+++ b/Telegram/SourceFiles/window/window_peer_menu.cpp
@@ -24,7 +24,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "apiwrap.h"
 #include "mainwidget.h"
 #include "mainwindow.h"
-#include "observer_peer.h"
 #include "api/api_common.h"
 #include "api/api_chat_filters.h"
 #include "history/history.h"
@@ -37,6 +36,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "info/info_controller.h"
 //#include "info/feed/info_feed_channels_controllers.h" // #feed
 #include "info/profile/info_profile_values.h"
+#include "data/data_changes.h"
 #include "data/data_session.h"
 #include "data/data_folder.h"
 #include "data/data_poll.h"
@@ -306,31 +306,23 @@ void Filler::addHidePromotion() {
 void Filler::addTogglePin() {
 	const auto filterId = _filterId;
 	const auto peer = _peer;
-	auto isPinned = false;
-	if (const auto history = peer->owner().historyLoaded(peer)) {
-		isPinned = history->isPinnedDialog(filterId);
-	}
-	const auto pinText = [](bool isPinned) {
-		return isPinned
+	const auto history = peer->owner().history(peer);
+	const auto pinText = [=] {
+		return history->isPinnedDialog(filterId)
 			? tr::lng_context_unpin_from_top(tr::now)
 			: tr::lng_context_pin_to_top(tr::now);
 	};
 	const auto pinToggle = [=] {
-		TogglePinnedDialog(
-			_controller,
-			peer->owner().history(peer),
-			filterId);
+		TogglePinnedDialog(_controller, history, filterId);
 	};
-	const auto pinAction = _addAction(pinText(isPinned), pinToggle);
+	const auto pinAction = _addAction(pinText(), pinToggle);
 
 	const auto lifetime = Ui::CreateChild<rpl::lifetime>(pinAction);
-	Notify::PeerUpdateViewer(
-		peer,
-		Notify::PeerUpdate::Flag::ChatPinnedChanged
+	history->session().changes().historyUpdates(
+		history,
+		Data::HistoryUpdate::Flag::IsPinned
 	) | rpl::start_with_next([=] {
-		const auto history = peer->owner().history(peer);
-		const auto isPinned = history->isPinnedDialog(filterId);
-		pinAction->setText(pinText(isPinned));
+		pinAction->setText(pinText());
 	}, *lifetime);
 }
 
@@ -357,20 +349,18 @@ void Filler::addInfo() {
 
 void Filler::addToggleUnreadMark() {
 	const auto peer = _peer;
-	const auto isUnread = [](not_null<PeerData*> peer) {
-		if (const auto history = peer->owner().historyLoaded(peer)) {
-			return (history->chatListUnreadCount() > 0)
-				|| (history->chatListUnreadMark());
-		}
-		return false;
+	const auto history = peer->owner().history(peer);
+	const auto isUnread = [=] {
+		return (history->chatListUnreadCount() > 0)
+			|| (history->chatListUnreadMark());
 	};
-	const auto label = [=](not_null<PeerData*> peer) {
-		return isUnread(peer)
+	const auto label = [=] {
+		return isUnread()
 			? tr::lng_context_mark_read(tr::now)
 			: tr::lng_context_mark_unread(tr::now);
 	};
-	auto action = _addAction(label(peer), [=] {
-		const auto markAsRead = isUnread(peer);
+	auto action = _addAction(label(), [=] {
+		const auto markAsRead = isUnread();
 		const auto handle = [&](not_null<History*> history) {
 			if (markAsRead) {
 				peer->owner().histories().readInbox(history);
@@ -380,7 +370,6 @@ void Filler::addToggleUnreadMark() {
 					!markAsRead);
 			}
 		};
-		const auto history = peer->owner().history(peer);
 		handle(history);
 		if (markAsRead) {
 			if (const auto migrated = history->migrateSibling()) {
@@ -390,24 +379,22 @@ void Filler::addToggleUnreadMark() {
 	});
 
 	const auto lifetime = Ui::CreateChild<rpl::lifetime>(action);
-	Notify::PeerUpdateViewer(
-		_peer,
-		Notify::PeerUpdate::Flag::UnreadViewChanged
+	history->session().changes().historyUpdates(
+		history,
+		Data::HistoryUpdate::Flag::UnreadView
 	) | rpl::start_with_next([=] {
-		action->setText(label(peer));
+		action->setText(label());
 	}, *lifetime);
 }
 
 void Filler::addToggleArchive() {
 	const auto peer = _peer;
+	const auto history = peer->owner().history(peer);
 	const auto isArchived = [=] {
-		const auto history = peer->owner().historyLoaded(peer);
-		return history && history->folder();
+		return (history->folder() != nullptr);
 	};
 	const auto toggle = [=] {
-		ToggleHistoryArchived(
-			peer->owner().history(peer),
-			!isArchived());
+		ToggleHistoryArchived(history, !isArchived());
 	};
 	const auto archiveAction = _addAction(
 		(isArchived()
@@ -416,9 +403,9 @@ void Filler::addToggleArchive() {
 		toggle);
 
 	const auto lifetime = Ui::CreateChild<rpl::lifetime>(archiveAction);
-	Notify::PeerUpdateViewer(
-		peer,
-		Notify::PeerUpdate::Flag::FolderChanged
+	history->session().changes().historyUpdates(
+		history,
+		Data::HistoryUpdate::Flag::Folder
 	) | rpl::start_with_next([=] {
 		archiveAction->setText(isArchived()
 			? tr::lng_archived_remove(tr::now)
@@ -448,9 +435,9 @@ void Filler::addBlockUser(not_null<UserData*> user) {
 	});
 
 	const auto lifetime = Ui::CreateChild<rpl::lifetime>(blockAction);
-	Notify::PeerUpdateViewer(
+	_peer->session().changes().peerUpdates(
 		_peer,
-		Notify::PeerUpdate::Flag::UserIsBlocked
+		Data::PeerUpdate::Flag::IsBlocked
 	) | rpl::start_with_next([=] {
 		blockAction->setText(blockText(user));
 	}, *lifetime);