diff --git a/package.yaml b/package.yaml
index 1946a5005..fab70a13f 100644
--- a/package.yaml
+++ b/package.yaml
@@ -1,5 +1,5 @@
 name: simplexmq
-version: 4.2.0
+version: 4.2.1
 synopsis: SimpleXMQ message broker
 description: |
   This package includes <./docs/Simplex-Messaging-Server.html server>,
diff --git a/simplexmq.cabal b/simplexmq.cabal
index a2c25d487..d1858104f 100644
--- a/simplexmq.cabal
+++ b/simplexmq.cabal
@@ -5,7 +5,7 @@ cabal-version: 1.12
 -- see: https://github.com/sol/hpack
 
 name:           simplexmq
-version:        4.2.0
+version:        4.2.1
 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/Transport.hs b/src/Simplex/Messaging/Transport.hs
index 8d67202b4..5f688f8f6 100644
--- a/src/Simplex/Messaging/Transport.hs
+++ b/src/Simplex/Messaging/Transport.hs
@@ -100,7 +100,7 @@ supportedSMPServerVRange :: VersionRange
 supportedSMPServerVRange = mkVersionRange 1 5
 
 simplexMQVersion :: String
-simplexMQVersion = "4.2.0"
+simplexMQVersion = "4.2.1"
 
 -- * Transport connection class