Users of distributed systems that rely on serialization to exchange objects (such as akka) should upgrade to Scala 2.11.1 (and akka 2.3.3) immediately. We also strongly recommend that libraries that themselves declare classes with @SerialVersionUID annotations release a new version and ask their Scala 2.11 users to upgrade.
https://groups.google.com/forum/#!topic/akka-user/mEcBXRr9Kto