--- Crypto.hs	2017-08-10 20:17:59.000000000 +0200
+++ Crypto.hs	2018-08-05 17:53:01.058720655 +0200
@@ -77,11 +77,11 @@
 	case Ed25519.publicKey pk of
 		CryptoPassed pk' -> SigVerifier 1 (Ed25519.verify pk')
 		CryptoFailed _ -> mempty
-
+instance Semigroup SigVerifier where
+	(SigVerifier na a) <> (SigVerifier nb b) =
+		SigVerifier (na+nb) $ \d s -> b d s || a d s
 instance Monoid SigVerifier where
 	mempty = SigVerifier 0 $ \_b _s -> False
-	mappend (SigVerifier na a) (SigVerifier nb b) =
-		SigVerifier (na+nb) $ \d s -> b d s || a d s
 
 data MySessionKey = MySessionKey Ed25519.SecretKey Ed25519.PublicKey
 
--- Types.hs	2017-08-10 20:17:59.000000000 +0200
+++ Types.hs	2018-08-05 17:51:29.435490869 +0200
@@ -194,9 +194,10 @@
 mkElapsedTime :: POSIXTime -> POSIXTime -> ElapsedTime
 mkElapsedTime start end = ElapsedTime $ fromRational $ toRational (end - start)
 
+instance Semigroup ElapsedTime where
+	(ElapsedTime a) <> (ElapsedTime b) = ElapsedTime (a+b)
 instance Monoid ElapsedTime where
 	mempty = ElapsedTime 0
-	mappend (ElapsedTime a) (ElapsedTime b) = ElapsedTime (a+b)
 
 instance DataSize ElapsedTime where
 	dataSize _ = 16 -- 128 bit Double
--- Val.hs	2017-08-10 20:17:59.000000000 +0200
+++ Val.hs	2018-08-05 17:50:22.926328293 +0200
@@ -19,7 +19,7 @@
 
 -- | Newtype of ByteString so we can have JSON instances without orphans.
 newtype Val = Val { val :: B.ByteString }
-	deriving (Show, Generic, Eq, Monoid)
+	deriving (Show, Generic, Eq, Monoid, Semigroup)
 
 instance DataSize Val where
 	dataSize (Val b) = fromIntegral (B.length b)