When we deprecate something, this generally means you will not see any further development from us on it. It also means that support on it will be hard to come by. Longer its deprecated the longer we aren’t using it, and the less knowledgable any of us will be on it.
You should be able to use the kotlin sdk inside your java apps. Not sure what exactly that would look like. But from what I understand you should be able to compile into your java apps.
We are facing interoperability issues during integration of Andriod Java app and RC Kotlin. The issue is w.r.t accessibility of Kotlin APIs from Andriod Java app. Request your feedback on this. Thanks.