diff --git a/package.yaml b/package.yaml
index 4f05628ea..897122846 100644
--- a/package.yaml
+++ b/package.yaml
@@ -1,5 +1,5 @@
 name: simplexmq
-version: 2.2.0
+version: 2.2.1
 synopsis: SimpleXMQ message broker
 description: |
   This package includes <./docs/Simplex-Messaging-Server.html server>,
diff --git a/simplexmq.cabal b/simplexmq.cabal
index 99cc897f6..7a4cb46de 100644
--- a/simplexmq.cabal
+++ b/simplexmq.cabal
@@ -5,7 +5,7 @@ cabal-version: 1.12
 -- see: https://github.com/sol/hpack
 
 name:           simplexmq
-version:        2.2.0
+version:        2.2.1
 synopsis:       SimpleXMQ message broker
 description:    This package includes <./docs/Simplex-Messaging-Server.html server>,
                 <./docs/Simplex-Messaging-Client.html client> and
diff --git a/src/Simplex/Messaging/Server.hs b/src/Simplex/Messaging/Server.hs
index 5b0ee4f5a..b43cad9cb 100644
--- a/src/Simplex/Messaging/Server.hs
+++ b/src/Simplex/Messaging/Server.hs
@@ -65,6 +65,7 @@ import qualified Simplex.Messaging.TMap as TM
 import Simplex.Messaging.Transport
 import Simplex.Messaging.Transport.Server
 import Simplex.Messaging.Util
+import System.Mem.Weak (deRefWeak)
 import UnliftIO.Concurrent
 import UnliftIO.Exception
 import UnliftIO.IO
@@ -196,6 +197,7 @@ clientDisconnected c@Client {subscriptions, connected} = do
   atomically $ writeTVar connected False
   subs <- readTVarIO subscriptions
   mapM_ cancelSub subs
+  atomically $ writeTVar subscriptions M.empty
   cs <- asks $ subscribers . server
   atomically . mapM_ (\rId -> TM.update deleteCurrentClient rId cs) $ M.keys subs
   where
@@ -210,7 +212,7 @@ sameClientSession Client {sessionId} Client {sessionId = s'} = sessionId == s'
 cancelSub :: MonadUnliftIO m => TVar Sub -> m ()
 cancelSub sub =
   readTVarIO sub >>= \case
-    Sub {subThread = SubThread t} -> killThread t
+    Sub {subThread = SubThread t} -> liftIO $ deRefWeak t >>= mapM_ killThread
     _ -> return ()
 
 receive :: (Transport c, MonadUnliftIO m, MonadReader Env m) => THandle c -> Client -> m ()
@@ -536,7 +538,7 @@ client clnt@Client {subscriptions, ntfSubscriptions, rcvQ, sndQ} Server {subscri
             forkSub :: m ()
             forkSub = do
               atomically . modifyTVar sub $ \s -> s {subThread = SubPending}
-              t <- forkIO subscriber
+              t <- mkWeakThreadId =<< forkIO subscriber
               atomically . modifyTVar sub $ \case
                 s@Sub {subThread = SubPending} -> s {subThread = SubThread t}
                 s -> s
diff --git a/src/Simplex/Messaging/Server/Env/STM.hs b/src/Simplex/Messaging/Server/Env/STM.hs
index 35f0dc051..1440486a3 100644
--- a/src/Simplex/Messaging/Server/Env/STM.hs
+++ b/src/Simplex/Messaging/Server/Env/STM.hs
@@ -32,6 +32,7 @@ import qualified Simplex.Messaging.TMap as TM
 import Simplex.Messaging.Transport (ATransport)
 import Simplex.Messaging.Transport.Server (loadFingerprint, loadTLSServerParams)
 import System.IO (IOMode (..))
+import System.Mem.Weak (Weak)
 import UnliftIO.STM
 
 data ServerConfig = ServerConfig
@@ -113,7 +114,7 @@ data ServerStats = ServerStats
     fromTime :: TVar UTCTime
   }
 
-data SubscriptionThread = NoSub | SubPending | SubThread ThreadId | ProhibitSub
+data SubscriptionThread = NoSub | SubPending | SubThread (Weak ThreadId) | ProhibitSub
 
 data Sub = Sub
   { subThread :: SubscriptionThread,
diff --git a/src/Simplex/Messaging/Transport.hs b/src/Simplex/Messaging/Transport.hs
index 221db1b65..680cc36b4 100644
--- a/src/Simplex/Messaging/Transport.hs
+++ b/src/Simplex/Messaging/Transport.hs
@@ -96,7 +96,7 @@ supportedSMPVersions :: VersionRange
 supportedSMPVersions = mkVersionRange 1 2
 
 simplexMQVersion :: String
-simplexMQVersion = "2.2.0"
+simplexMQVersion = "2.2.1"
 
 -- * Transport connection class