diff --git a/Session.hs b/Session.hs
index ca95457..fe7c025 100644
--- a/Session.hs
+++ b/Session.hs
@@ -13,6 +13,17 @@ import qualified Network.Protocol.XMPP as XMPP
 import qualified Config
 import Util
 
+cleanOld :: Config.Config -> XMPP.JID -> XMPP.XMPP ()
+cleanOld config source = do
+	old <- liftIO $ DB.query (Config.db config)
+		(s"SELECT target_muc, target_nick, source_nick FROM sessions WHERE version < ? AND source_muc = ?")
+		(Config.dbVersion config, bareTxt source)
+	forM_ old $ \(muc, nick, source_nick) ->
+		let Just target = XMPP.parseJID $ muc  ++ s"/" ++ nick in
+		sendPresence config ((XMPP.emptyPresence XMPP.PresenceUnavailable) {
+			XMPP.presenceFrom = XMPP.parseJID $ bareTxt source ++ s"/" ++ source_nick
+		}) target
+
 mkSession :: (MonadIO m) =>
 	   Config.Config
 	-> XMPP.PresenceType
@@ -26,13 +37,16 @@ mkSession config typ source target
 			(sourceMuc, sourceNick, targetMuc, targetNick)
 	| otherwise =
 		liftIO $ DB.execute (Config.db config)
-			(s"INSERT INTO sessions VALUES (?,?,?,?,?)")
-			(sourceMuc, sourceNick, targetMuc, targetNick, Config.dbVersion config)
+			(s"INSERT INTO sessions VALUES (?,?,?,?,?) ON CONFLICT(source_muc,source_nick,target_muc,target_nick) DO UPDATE SET version=?")
+			(
+				sourceMuc, sourceNick, targetMuc, targetNick,
+				Config.dbVersion config, Config.dbVersion config
+			)
 	where
-	sourceMuc = bareTxt <$> source
-	sourceNick = XMPP.strResource <$> (XMPP.jidResource =<< source)
+	sourceMuc = fromMaybe mempty (bareTxt <$> source)
+	sourceNick = fromMaybe mempty (XMPP.strResource <$> (XMPP.jidResource =<< source))
 	targetMuc = bareTxt target
-	targetNick = XMPP.strResource <$> XMPP.jidResource target
+	targetNick = fromMaybe mempty (XMPP.strResource <$> XMPP.jidResource target)
 
 maybeAddNick :: XMPP.JID -> Text -> XMPP.JID
 maybeAddNick jid@XMPP.JID { XMPP.jidResource = Just _ } _ = jid
@@ -94,7 +108,8 @@ sendGroupChat config message@XMPP.Message {
 	XMPP.messagePayloads = payloads
 } target = do
 		nickSwaps1 <- liftIO $ DB.query (Config.db config) (s"SELECT target_nick, source_nick FROM sessions WHERE source_muc=?") (DB.Only $ bareTxt target)
-		nickSwaps2 <- liftIO $ DB.query (Config.db config) (s"SELECT source_nick, target_nick FROM sessions WHERE target_muc=? AND source_muc IS NOT NULL") (DB.Only $ bareTxt target)
+		nickSwaps2 <- liftIO $ DB.query (Config.db config) (s"SELECT source_nick, target_nick FROM sessions WHERE target_muc=? AND source_muc <> ''") (DB.Only $ bareTxt target)
+		let nickSwap = replaceWords (nickSwaps1 ++ nickSwaps2)
 		XMPP.putStanza $ message {
 			XMPP.messageFrom = Just (proxyJid config from),
 			XMPP.messageTo = Just target,
@@ -103,8 +118,7 @@ sendGroupChat config message@XMPP.Message {
 					[body] ->
 						body { XML.elementNodes = [
 							XML.NodeContent $ XML.ContentText $
-								replaceWords (nickSwaps1 ++ nickSwaps2)
-								(mconcat (XML.elementText body))
+								nickSwap (mconcat (XML.elementText body))
 						]}
 					_ -> el
 			) payloads
diff --git a/gateway.hs b/gateway.hs
index 25f7aab..2e4aebb 100644
--- a/gateway.hs
+++ b/gateway.hs
@@ -40,7 +40,8 @@ handlePresence config presence@XMPP.Presence {
 	| bareTxt to /= bareTxt (Config.bridgeJid config) =
 		-- This is to one of our ghosts, so just ignore it
 		return ()
-	| hasMucCode 110 presence = return () -- ignore self presence
+	| hasMucCode 110 presence = -- done joining room, clean up old data
+		Session.cleanOld config from
 	| Just resource <- XMPP.jidResource from,
 	  not (s"[x]" `T.isInfixOf` XMPP.strResource resource) = forM_ (targets config from) $
 		Session.sendPresence config presence