diff --git a/CHANGELOG.md b/CHANGELOG.md
index e05d6d29..4ca18266 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Change Log
 
+## [1.2.21](https://github.com/ably/ably-go/tree/v1.2.21)
+
+[Full Changelog](https://github.com/ably/ably-go/compare/v1.2.20...v1.2.21)
+
+**Implemented enhancements:**
+
+- JWT (JSON Web Token) authentication [\#569](https://github.com/ably/ably-go/issues/569)
+
 ## [1.2.20](https://github.com/ably/ably-go/tree/v1.2.20)
 
 [Full Changelog](https://github.com/ably/ably-go/compare/v1.2.19...v1.2.20)
diff --git a/ably/proto_http.go b/ably/proto_http.go
index 26f062a7..d44b0b97 100644
--- a/ably/proto_http.go
+++ b/ably/proto_http.go
@@ -11,7 +11,7 @@ const (
 	ablyProtocolVersionHeader = "X-Ably-Version"
 	ablyErrorCodeHeader       = "X-Ably-Errorcode"
 	ablyErrorMessageHeader    = "X-Ably-Errormessage"
-	clientLibraryVersion      = "1.2.20"
+	clientLibraryVersion      = "1.2.21"
 	clientRuntimeName         = "go"
 	ablyProtocolVersion       = "2" // CSV2
 	ablyClientIDHeader        = "X-Ably-ClientId"