diff --git a/Telegram/SourceFiles/calls/calls_call.h b/Telegram/SourceFiles/calls/calls_call.h
index 2075be7ab..7bfef7ba6 100644
--- a/Telegram/SourceFiles/calls/calls_call.h
+++ b/Telegram/SourceFiles/calls/calls_call.h
@@ -191,6 +191,7 @@ private:
 		Ended,
 		Failed,
 	};
+
 	void handleRequestError(const RPCError &error);
 	void handleControllerError(const QString &error);
 	void finish(
diff --git a/Telegram/SourceFiles/calls/calls_group_call.cpp b/Telegram/SourceFiles/calls/calls_group_call.cpp
index 0dcd19e6b..15ff367de 100644
--- a/Telegram/SourceFiles/calls/calls_group_call.cpp
+++ b/Telegram/SourceFiles/calls/calls_group_call.cpp
@@ -25,7 +25,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 //#include "calls/calls_panel.h"
 //#include "webrtc/webrtc_video_track.h"
 //#include "webrtc/webrtc_media_devices.h"
+#include "data/data_changes.h"
 #include "data/data_channel.h"
+#include "data/data_group_call.h"
 //#include "data/data_session.h"
 //#include "facades.h"
 
@@ -49,6 +51,7 @@ GroupCall::GroupCall(
 , _channel(channel)
 , _api(&_channel->session().mtp()) {
 	if (inputCall.c_inputGroupCall().vid().v) {
+		_state = State::Joining;
 		join(inputCall);
 	} else {
 		start();
@@ -59,19 +62,51 @@ GroupCall::~GroupCall() {
 	destroyController();
 }
 
+void GroupCall::setState(State state) {
+	if (_state.current() == State::Failed) {
+		return;
+	} else if (_state.current() == State::FailedHangingUp
+		&& state != State::Failed) {
+		return;
+	}
+	if (_state.current() == state) {
+		return;
+	}
+	_state = state;
+
+	if (false
+		|| state == State::Ended
+		|| state == State::Failed) {
+		// Destroy controller before destroying Call Panel,
+		// so that the panel hide animation is smooth.
+		destroyController();
+	}
+	switch (state) {
+	case State::Ended:
+		_delegate->groupCallFinished(this);
+		break;
+	case State::Failed:
+		_delegate->groupCallFailed(this);
+		break;
+	}
+}
+
 void GroupCall::start() {
 	const auto randomId = rand_value<int32>();
 	_api.request(MTPphone_CreateGroupCall(
 		_channel->inputChannel,
 		MTP_int(randomId)
 	)).done([=](const MTPUpdates &result) {
+		_acceptFields = true;
 		_channel->session().api().applyUpdates(result);
+		_acceptFields = false;
 	}).fail([=](const RPCError &error) {
 		int a = error.code();
 	}).send();
 }
 
 void GroupCall::join(const MTPInputGroupCall &inputCall) {
+	setState(State::Joining);
 	inputCall.match([&](const MTPDinputGroupCall &data) {
 		_id = data.vid().v;
 		_accessHash = data.vaccess_hash().v;
@@ -91,10 +126,11 @@ void GroupCall::join(const MTPInputGroupCall &inputCall) {
 				}
 
 				auto root = QJsonObject();
+				const auto ssrc = payload.ssrc;
 				root.insert("ufrag", QString::fromStdString(payload.ufrag));
 				root.insert("pwd", QString::fromStdString(payload.pwd));
 				root.insert("fingerprints", fingerprints);
-				root.insert("ssrc", int(payload.ssrc));
+				root.insert("ssrc", double(payload.ssrc));
 
 				const auto json = QJsonDocument(root).toJson(
 					QJsonDocument::Compact);
@@ -105,6 +141,9 @@ void GroupCall::join(const MTPInputGroupCall &inputCall) {
 					inputCall,
 					MTP_dataJSON(MTP_bytes(json))
 				)).done([=](const MTPUpdates &updates) {
+					_mySsrc = ssrc;
+					setState(State::Joined);
+
 					_channel->session().api().applyUpdates(updates);
 				}).fail([=](const RPCError &error) {
 					int a = error.code();
@@ -112,6 +151,77 @@ void GroupCall::join(const MTPInputGroupCall &inputCall) {
 			});
 		});
 	});
+	_channel->setCall(inputCall);
+
+	_channel->session().changes().peerFlagsValue(
+		_channel,
+		Data::PeerUpdate::Flag::GroupCall
+	) | rpl::start_with_next([=] {
+		checkParticipants();
+	}, _lifetime);
+}
+
+void GroupCall::checkParticipants() {
+	if (!joined()) {
+		return;
+	}
+	const auto call = _channel->call();
+	if (!call || call->id() != _id) {
+		finish(FinishType::Ended);
+		return;
+	}
+	const auto &sources = call->sources();
+	if (sources.size() != call->fullCount() || sources.empty()) {
+		call->reload();
+		return;
+	}
+	auto ssrcs = std::vector<uint32_t>();
+	ssrcs.reserve(sources.size());
+	for (const auto source : sources) {
+		if (source != _mySsrc) {
+			ssrcs.push_back(source);
+		}
+	}
+	_instance->setSsrcs(std::move(ssrcs));
+	_instance->setIsMuted(false);
+}
+
+void GroupCall::hangup() {
+	finish(FinishType::Ended);
+}
+
+void GroupCall::finish(FinishType type) {
+	Expects(type != FinishType::None);
+
+	const auto finalState = (type == FinishType::Ended)
+		? State::Ended
+		: State::Failed;
+	const auto hangupState = (type == FinishType::Ended)
+		? State::HangingUp
+		: State::FailedHangingUp;
+	const auto state = _state.current();
+	if (state == State::HangingUp
+		|| state == State::FailedHangingUp
+		|| state == State::Ended
+		|| state == State::Failed) {
+		return;
+	}
+	if (!joined()) {
+		setState(finalState);
+		return;
+	}
+
+	setState(hangupState);
+	_api.request(MTPphone_LeaveGroupCall(
+		inputCall()
+	)).done([=](const MTPUpdates &result) {
+		// Here 'this' could be destroyed by updates, so we set Ended after
+		// updates being handled, but in a guarded way.
+		crl::on_main(this, [=] { setState(finalState); });
+		_channel->session().api().applyUpdates(result);
+	}).fail([=](const RPCError &error) {
+		setState(finalState);
+	}).send();
 }
 
 void GroupCall::setMuted(bool mute) {
@@ -123,7 +233,13 @@ void GroupCall::setMuted(bool mute) {
 
 bool GroupCall::handleUpdate(const MTPGroupCall &call) {
 	return call.match([&](const MTPDgroupCall &data) {
-		if (_id != data.vid().v
+		if (_acceptFields) {
+			if (_instance || _id) {
+				return false;
+			}
+			join(MTP_inputGroupCall(data.vid(), data.vaccess_hash()));
+			return true;
+		} else if (_id != data.vid().v
 			|| _accessHash != data.vaccess_hash().v
 			|| !_instance) {
 			return false;
@@ -182,35 +298,10 @@ bool GroupCall::handleUpdate(const MTPGroupCall &call) {
 					});
 				}
 				_instance->setJoinResponsePayload(payload);
-				_api.request(MTPphone_GetGroupParticipants(
-					inputCall(),
-					MTP_int(0),
-					MTP_int(10)
-				)).done([=](const MTPphone_GroupParticipants &result) {
-					auto sources = std::vector<uint32_t>();
-					result.match([&](const MTPDphone_groupParticipants &data) {
-						for (const auto &p : data.vparticipants().v) {
-							p.match([&](const MTPDgroupCallParticipant &data) {
-								if (data.vuser_id().v != _channel->session().userId()) {
-									sources.push_back(data.vsource().v);
-								}
-							});
-						}
-					});
-					_instance->setSsrcs(std::move(sources));
-					_instance->setIsMuted(false);
-				}).fail([=](const RPCError &error) {
-					int a = error.code();
-				}).send();
+				checkParticipants();
 			});
 		}
 		return true;
-	}, [&](const MTPDgroupCallPrivate &data) {
-		if (_instance || _id) {
-			return false;
-		}
-		join(MTP_inputGroupCall(data.vid(), data.vaccess_hash()));
-		return true;
 	}, [&](const MTPDgroupCallDiscarded &data) {
 		if (data.vid().v != _id) {
 			return false;
diff --git a/Telegram/SourceFiles/calls/calls_group_call.h b/Telegram/SourceFiles/calls/calls_group_call.h
index 412a8e168..6286f3de5 100644
--- a/Telegram/SourceFiles/calls/calls_group_call.h
+++ b/Telegram/SourceFiles/calls/calls_group_call.h
@@ -25,6 +25,9 @@ public:
 	public:
 		virtual ~Delegate() = default;
 
+		virtual void groupCallFinished(not_null<GroupCall*> call) = 0;
+		virtual void groupCallFailed(not_null<GroupCall*> call) = 0;
+
 	};
 
 	GroupCall(
@@ -38,6 +41,7 @@ public:
 	}
 
 	void start();
+	void hangup();
 	void join(const MTPInputGroupCall &inputCall);
 	bool handleUpdate(const MTPGroupCall &call);
 
@@ -48,6 +52,25 @@ public:
 	[[nodiscard]] rpl::producer<bool> mutedValue() const {
 		return _muted.value();
 	}
+	[[nodiscard]] bool joined() const {
+		return _mySsrc != 0;
+	}
+
+	enum State {
+		Creating,
+		Joining,
+		Joined,
+		FailedHangingUp,
+		Failed,
+		HangingUp,
+		Ended,
+	};
+	[[nodiscard]] State state() const {
+		return _state.current();
+	}
+	[[nodiscard]] rpl::producer<State> stateValue() const {
+		return _state.value();
+	}
 
 	void setCurrentAudioDevice(bool input, const QString &deviceId);
 	void setAudioVolume(bool input, float level);
@@ -58,22 +81,34 @@ public:
 	}
 
 private:
+	enum class FinishType {
+		None,
+		Ended,
+		Failed,
+	};
+
 	void handleRequestError(const RPCError &error);
 	void handleControllerError(const QString &error);
 	void createAndStartController();
 	void destroyController();
+	void checkParticipants();
+
+	void setState(State state);
+	void finish(FinishType type);
 
 	[[nodiscard]] MTPInputGroupCall inputCall() const;
 
 	const not_null<Delegate*> _delegate;
 	const not_null<ChannelData*> _channel;
 	MTP::Sender _api;
-	crl::time _startTime = 0;
+	rpl::variable<State> _state = State::Creating;
 
 	rpl::variable<bool> _muted = false;
+	bool _acceptFields = false;
 
 	uint64 _id = 0;
 	uint64 _accessHash = 0;
+	uint32 _mySsrc = 0;
 
 	std::unique_ptr<tgcalls::GroupInstanceImpl> _instance;
 
diff --git a/Telegram/SourceFiles/calls/calls_instance.cpp b/Telegram/SourceFiles/calls/calls_instance.cpp
index b0cd55288..9dd83f4ec 100644
--- a/Telegram/SourceFiles/calls/calls_instance.cpp
+++ b/Telegram/SourceFiles/calls/calls_instance.cpp
@@ -17,6 +17,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "calls/calls_call.h"
 #include "calls/calls_panel.h"
 #include "data/data_user.h"
+#include "data/data_group_call.h"
 #include "data/data_channel.h"
 #include "data/data_session.h"
 #include "media/audio/media_audio_track.h"
@@ -93,6 +94,18 @@ void Instance::callRedial(not_null<Call*> call) {
 	}
 }
 
+void Instance::groupCallFinished(not_null<GroupCall*> call) {
+	crl::on_main(call, [=] {
+		destroyGroupCall(call);
+	});
+}
+
+void Instance::groupCallFailed(not_null<GroupCall*> call) {
+	crl::on_main(call, [=] {
+		destroyGroupCall(call);
+	});
+}
+
 void Instance::playSound(Sound sound) {
 	switch (sound) {
 	case Sound::Busy: {
@@ -351,6 +364,12 @@ void Instance::handleCallUpdate(
 void Instance::handleGroupCallUpdate(
 		not_null<Main::Session*> session,
 		const MTPGroupCall &call) {
+	const auto callId = call.match([](const auto &data) {
+		return data.vid().v;
+	});
+	if (const auto existing = session->data().groupCall(callId)) {
+		existing->applyUpdate(call);
+	}
 	if (_currentGroupCall) {
 		_currentGroupCall->handleUpdate(call);
 	}
@@ -359,6 +378,12 @@ void Instance::handleGroupCallUpdate(
 void Instance::handleGroupCallUpdate(
 		not_null<Main::Session*> session,
 		const MTPDupdateGroupCallParticipants &update) {
+	const auto callId = update.vcall().match([](const auto &data) {
+		return data.vid().v;
+	});
+	if (const auto existing = session->data().groupCall(callId)) {
+		existing->applyUpdate(update);
+	}
 }
 
 void Instance::handleSignalingData(
@@ -424,7 +449,7 @@ void Instance::requestPermissionOrFail(Platform::PermissionType type, Fn<void()>
 			_currentCall->hangup();
 		}
 		if (inGroupCall()) {
-			//_currentGroupCall->hangup(); // #TODO calls
+			_currentGroupCall->hangup();
 		}
 		Ui::show(Box<ConfirmBox>(tr::lng_no_mic_permission(tr::now), tr::lng_menu_settings(tr::now), crl::guard(this, [=] {
 			Platform::OpenSystemSettingsForPermission(type);
diff --git a/Telegram/SourceFiles/calls/calls_instance.h b/Telegram/SourceFiles/calls/calls_instance.h
index 390292b97..2c2c2a761 100644
--- a/Telegram/SourceFiles/calls/calls_instance.h
+++ b/Telegram/SourceFiles/calls/calls_instance.h
@@ -70,6 +70,9 @@ private:
 		requestPermissionsOrFail(std::move(onSuccess));
 	}
 
+	void groupCallFinished(not_null<GroupCall*> call) override;
+	void groupCallFailed(not_null<GroupCall*> call) override;
+
 	using Sound = Call::Delegate::Sound;
 	void playSound(Sound sound) override;
 	void createCall(not_null<UserData*> user, Call::Type type, bool video);
diff --git a/Telegram/SourceFiles/data/data_group_call.cpp b/Telegram/SourceFiles/data/data_group_call.cpp
index 147c23ed4..97192f76d 100644
--- a/Telegram/SourceFiles/data/data_group_call.cpp
+++ b/Telegram/SourceFiles/data/data_group_call.cpp
@@ -29,10 +29,19 @@ GroupCall::GroupCall(
 , _accessHash(accessHash) {
 }
 
+GroupCall::~GroupCall() {
+	_channel->session().api().request(_participantsRequestId).cancel();
+	_channel->session().api().request(_reloadRequestId).cancel();
+}
+
 uint64 GroupCall::id() const {
 	return _id;
 }
 
+not_null<ChannelData*> GroupCall::channel() const {
+	return _channel;
+}
+
 MTPInputGroupCall GroupCall::input() const {
 	return MTP_inputGroupCall(MTP_long(_id), MTP_long(_accessHash));
 }
@@ -42,8 +51,12 @@ auto GroupCall::participants() const
 	return _participants;
 }
 
+const base::flat_set<uint32> &GroupCall::sources() const {
+	return _sources;
+}
+
 void GroupCall::requestParticipants() {
-	if (_participantsRequestId) {
+	if (_participantsRequestId || _reloadRequestId) {
 		return;
 	} else if (_participants.size() >= _fullCount && _allReceived) {
 		return;
@@ -58,31 +71,9 @@ void GroupCall::requestParticipants() {
 		MTP_int(kRequestPerPage)
 	)).done([=](const MTPphone_GroupParticipants &result) {
 		result.match([&](const MTPDphone_groupParticipants &data) {
-			_fullCount = data.vcount().v;
 			_channel->owner().processUsers(data.vusers());
-			for (const auto &p : data.vparticipants().v) {
-				p.match([&](const MTPDgroupCallParticipant &data) {
-					const auto userId = data.vuser_id().v;
-					const auto user = _channel->owner().user(userId);
-					const auto value = Participant{
-						.user = user,
-						.date = data.vdate().v,
-						.source = data.vsource().v,
-						.muted = data.is_muted(),
-						.canSelfUnmute = data.is_can_self_unmute(),
-						.left = data.is_left()
-					};
-					const auto i = ranges::find(
-						_participants,
-						user,
-						&Participant::user);
-					if (i == end(_participants)) {
-						_participants.push_back(value);
-					} else {
-						*i = value;
-					}
-				});
-			}
+			applyParticipantsSlice(data.vparticipants().v);
+			_fullCount = data.vcount().v;
 			if (!_allReceived
 				&& (data.vparticipants().v.size() < kRequestPerPage)) {
 				_allReceived = true;
@@ -91,16 +82,17 @@ void GroupCall::requestParticipants() {
 				_fullCount = _participants.size();
 			}
 		});
-		ranges::sort(_participants, std::greater<>(), &Participant::date);
 		_channel->session().changes().peerUpdated(
 			_channel,
 			PeerUpdate::Flag::GroupCall);
+		_participantsRequestId = 0;
 	}).fail([=](const RPCError &error) {
-		_allReceived = true;
 		_fullCount = _participants.size();
+		_allReceived = true;
 		_channel->session().changes().peerUpdated(
 			_channel,
 			PeerUpdate::Flag::GroupCall);
+		_participantsRequestId = 0;
 	}).send();
 }
 
@@ -112,4 +104,118 @@ bool GroupCall::participantsLoaded() const {
 	return _allReceived;
 }
 
+void GroupCall::applyUpdate(const MTPGroupCall &update) {
+	applyCall(update, false);
+}
+
+void GroupCall::applyCall(const MTPGroupCall &call, bool force) {
+	call.match([&](const MTPDgroupCall &data) {
+		const auto changed = (_version != data.vversion().v)
+			|| (_fullCount != data.vparticipants_count().v);
+		if (!force && !changed) {
+			return;
+		} else if (!force && _version > data.vversion().v) {
+			reload();
+			return;
+		}
+		_version = data.vversion().v;
+		_fullCount = data.vparticipants_count().v;
+	}, [&](const MTPDgroupCallDiscarded &data) {
+		const auto changed = (_duration != data.vduration().v)
+			|| !_finished;
+		if (!force && !changed) {
+			return;
+		}
+		_finished = true;
+		_duration = data.vduration().v;
+	});
+	_channel->session().changes().peerUpdated(
+		_channel,
+		PeerUpdate::Flag::GroupCall);
+}
+
+void GroupCall::reload() {
+	if (_reloadRequestId) {
+		return;
+	} else if (_participantsRequestId) {
+		_channel->session().api().request(_participantsRequestId).cancel();
+		_participantsRequestId = 0;
+	}
+	_reloadRequestId = _channel->session().api().request(
+		MTPphone_GetGroupCall(input())
+	).done([=](const MTPphone_GroupCall &result) {
+		result.match([&](const MTPDphone_groupCall &data) {
+			_channel->owner().processUsers(data.vusers());
+			_participants.clear();
+			_sources.clear();
+			applyParticipantsSlice(data.vparticipants().v);
+			for (const auto &source : data.vsources().v) {
+				_sources.emplace(source.v);
+			}
+			_fullCount = _sources.size();
+			if (_participants.size() > _fullCount) {
+				_fullCount = _participants.size();
+			}
+			_allReceived = (_fullCount == _participants.size());
+			applyCall(data.vcall(), true);
+		});
+		_reloadRequestId = 0;
+	}).fail([=](const RPCError &error) {
+		_reloadRequestId = 0;
+	}).send();
+}
+
+void GroupCall::applyParticipantsSlice(
+		const QVector<MTPGroupCallParticipant> &list) {
+	for (const auto &participant : list) {
+		participant.match([&](const MTPDgroupCallParticipant &data) {
+			const auto userId = data.vuser_id().v;
+			const auto user = _channel->owner().user(userId);
+			const auto i = ranges::find(
+				_participants,
+				user,
+				&Participant::user);
+			if (data.is_left()) {
+				if (i != end(_participants)) {
+					_sources.remove(i->source);
+					_participants.erase(i);
+				}
+				if (_fullCount > _participants.size()) {
+					--_fullCount;
+				}
+				return;
+			}
+			const auto value = Participant{
+				.user = user,
+				.date = data.vdate().v,
+				.source = uint32(data.vsource().v),
+				.muted = data.is_muted(),
+				.canSelfUnmute = data.is_can_self_unmute(),
+			};
+			if (i == end(_participants)) {
+				_participants.push_back(value);
+				++_fullCount;
+			} else {
+				*i = value;
+			}
+			_sources.emplace(uint32(data.vsource().v));
+		});
+	}
+	ranges::sort(_participants, std::greater<>(), &Participant::date);
+}
+
+void GroupCall::applyUpdate(const MTPDupdateGroupCallParticipants &update) {
+	if (update.vversion().v <= _version) {
+		return;
+	} else if (update.vversion().v != _version + 1) {
+		reload();
+		return;
+	}
+	_version = update.vversion().v;
+	applyParticipantsSlice(update.vparticipants().v);
+	_channel->session().changes().peerUpdated(
+		_channel,
+		PeerUpdate::Flag::GroupCall);
+}
+
 } // namespace Data
diff --git a/Telegram/SourceFiles/data/data_group_call.h b/Telegram/SourceFiles/data/data_group_call.h
index c72c20de4..add71d960 100644
--- a/Telegram/SourceFiles/data/data_group_call.h
+++ b/Telegram/SourceFiles/data/data_group_call.h
@@ -15,38 +15,52 @@ namespace Data {
 class GroupCall final {
 public:
 	GroupCall(not_null<ChannelData*> channel, uint64 id, uint64 accessHash);
+	~GroupCall();
 
 	[[nodiscard]] uint64 id() const;
+	[[nodiscard]] not_null<ChannelData*> channel() const;
 	[[nodiscard]] MTPInputGroupCall input() const;
 
 	struct Participant {
 		not_null<UserData*> user;
 		TimeId date = 0;
-		int source = 0;
+		uint32 source = 0;
 		bool muted = false;
 		bool canSelfUnmute = false;
-		bool left = false;
 	};
 
 	[[nodiscard]] auto participants() const
 		-> const std::vector<Participant> &;
+	[[nodiscard]] const base::flat_set<uint32> &sources() const;
 	void requestParticipants();
 	[[nodiscard]] bool participantsLoaded() const;
 
+	void applyUpdate(const MTPGroupCall &update);
+	void applyUpdate(const MTPDupdateGroupCallParticipants &update);
+
 	[[nodiscard]] int fullCount() const;
 
+	void reload();
+	[[nodiscard]] bool finished() const;
+	[[nodiscard]] int duration() const;
+
 private:
+	void applyCall(const MTPGroupCall &call, bool force);
+	void applyParticipantsSlice(const QVector<MTPGroupCallParticipant> &list);
+
 	const not_null<ChannelData*> _channel;
 	const uint64 _id = 0;
 	const uint64 _accessHash = 0;
 
 	int _version = 0;
-	UserId _adminId = 0;
-	uint64 _reflectorId = 0;
 	mtpRequestId _participantsRequestId = 0;
+	mtpRequestId _reloadRequestId = 0;
 
 	std::vector<Participant> _participants;
+	base::flat_set<uint32> _sources;
 	int _fullCount = 0;
+	int _duration = 0;
+	bool _finished = false;
 	bool _allReceived = false;
 
 };
diff --git a/Telegram/SourceFiles/data/data_session.cpp b/Telegram/SourceFiles/data/data_session.cpp
index 924c61179..c0b5cedf6 100644
--- a/Telegram/SourceFiles/data/data_session.cpp
+++ b/Telegram/SourceFiles/data/data_session.cpp
@@ -38,6 +38,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #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_group_call.h"
 #include "data/data_media_types.h"
 #include "data/data_folder.h"
 #include "data/data_channel.h"
@@ -791,6 +792,19 @@ void Session::applyMaximumChatVersions(const MTPVector<MTPChat> &data) {
 	}
 }
 
+void Session::registerGroupCall(not_null<GroupCall*> call) {
+	_groupCalls.emplace(call->id(), call);
+}
+
+void Session::unregisterGroupCall(not_null<GroupCall*> call) {
+	_groupCalls.remove(call->id());
+}
+
+GroupCall *Session::groupCall(uint64 callId) const {
+	const auto i = _groupCalls.find(callId);
+	return (i != end(_groupCalls)) ? i->second.get() : nullptr;
+}
+
 PeerData *Session::peerByUsername(const QString &username) const {
 	const auto uname = username.trimmed();
 	for (const auto &[peerId, peer] : _peers) {
diff --git a/Telegram/SourceFiles/data/data_session.h b/Telegram/SourceFiles/data/data_session.h
index 4474e89b5..fc2fd3b46 100644
--- a/Telegram/SourceFiles/data/data_session.h
+++ b/Telegram/SourceFiles/data/data_session.h
@@ -60,6 +60,7 @@ class Histories;
 class DocumentMedia;
 class PhotoMedia;
 class Stickers;
+class GroupCall;
 
 class Session final {
 public:
@@ -153,6 +154,10 @@ public:
 
 	void applyMaximumChatVersions(const MTPVector<MTPChat> &data);
 
+	void registerGroupCall(not_null<GroupCall*> call);
+	void unregisterGroupCall(not_null<GroupCall*> call);
+	GroupCall *groupCall(uint64 callId) const;
+
 	void enumerateUsers(Fn<void(not_null<UserData*>)> action) const;
 	void enumerateGroups(Fn<void(not_null<PeerData*>)> action) const;
 	void enumerateChannels(Fn<void(not_null<ChannelData*>)> action) const;
@@ -906,6 +911,8 @@ private:
 
 	base::flat_set<not_null<ViewElement*>> _heavyViewParts;
 
+	base::flat_map<uint64, not_null<GroupCall*>> _groupCalls;
+
 	History *_topPromoted = nullptr;
 
 	NotifySettings _defaultUserNotifySettings;