Five weeks after the release of the very well received version 2.0, we have accumulated enough small fixes and enhancements to warrant a binary compatible bugfix release.

We would like to thank our great community for not only reporting, but also helping in fixing the issues which turned up: starting from very precise diagnostic information, over fixing errors in the documentation to submitting complete pull requests for performance enhancement. Special thanks go to Jean-François Im, Mathias Doenitz and Vibul Imtarnasan!

The issues fixed are:

• improved Java API for accessing singletons like akka.routing.CurrentRoutees and friends (also our beloved PoisonPill)
• reject invalid ActorSystem names which lead to problems when going remote (essentially must be valid hostname components now)
• fixed a live-lock in ForkJoinPool which could occur under rare circumstances with parallelism levels 2 or 4
• reduced overhead of ask(): less memory footprint and lazy registration
• several improvements and fixes for documentation (ScalaDoc as well as reStructuredText)
• make cause and message of AskTimeoutException accessible
• make SmallestMailboxRouter config serializable (this might require recompilation of classes mixing in SmallestMailboxLike)
• fix SmallestMailboxRouter crash upon sending under pressure
• make RemoteLifeCycleEvents serializable
• fix TestActorRef for actors setting ReceiveTimeout in constructor
• fix zeromq performance and instabilities by running the polling loop only on the same thread as all other activities for the socket
• never restart zeromq socket actors in case of fatal socket errors
• opened up visibility of RemoteTransport.send() and notifyListeners() to improve extensibility

Useful Links

• Akka Maven repository: https://repo.akka.io/releases
• Akka binary distribution: https://akka.io/downloads
• Akka 2.0.1 documentation: https://doc.akka.io/docs/akka/2.0.5/
• Issue tracker: https://app.assembla.com/spaces/akka/
• Akka mailing list: https://groups.google.com/g/akka-user

Akka is released under the Apache V2 license.

Happy Hakking!