The following modules of Akka are marked as experimental, which means that they are in early access mode, which also means that they are not covered by commercial support. The purpose of releasing them early, as experimental, is to make them easily available and improve based on feedback, or even discover that the module wasn't useful.
An experimental module doesn't have to obey the rule of staying binary compatible between micro releases. Breaking API changes may be introduced in minor releases without notice as we refine and simplify based on your feedback. An experimental module may be dropped in minor releases without prior deprecation.
Another reason for marking a module as experimental is that it's too early to tell if the module has a maintainer that can take the responsibility of the module over time. These modules live in the akka-contrib subproject: