Migration from Apache Pekko 1.x to 2.x

Apache Pekko 2.x is not Binary Compatible with Apache Pekko 1.x.

The major difference is that some deprecated code has been removed but there are also a small number of breaking changes where deprecation was not feasible.

It is possible that some simple code compiled with Pekko 1.x libs will work with Pekko 2.x but you should not rely on this.

Pekko 1.x is still maintained and major bugs will be fixed in it.

Start by upgrading to latest Pekko 1.x releases

Some of the changes in Pekko 2.x have been backported although these changes are normally only done when they fix important bugs.

Some additional code has been deprecated in the most recent 1.x releases and the compile warnings will help you with moving onto better supported APIs.

Change any code that relies on deprecated APIs in Pekko 1.x

Not every deprecated API has been removed in Pekko 2.x but many have been.

Java API users may find that they have more deprecations to deal with because the Scala API is more stable and there were a few mistakes in the Java API where Scala classes leaked into some of the Java API methods.

Additional Breaking Changes in Pekko 2.x

An example is in the Scala DSL for Flow and Source, the watchTermination function call no longer needs an empty param list before a second param list. Instead of watchTermination(){ ... }, you now must use watchTermination{ ... }. (PR2378)