I moved to back endless 5.2.0 in android.
now the register device is deprecated. and the new method don’t ask me GCM anymore.
is it OK
still I can not unregister from channel.
getting the error:
2018-11-21 11:29:10.328 14491-14491/com.repocyber.repoapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.repocyber.repoapp, PID: 14491
java.lang.RuntimeException: Could not unregister device on Backendless server: BackendlessFault{ code: ‘Server.Processing’, message: ‘no transaction is in progress’, detail: ‘no transaction is in progress’, extendedData: ‘{}’ }
at com.backendless.push.BackendlessPushService.onError(BackendlessPushService.java:252)
at com.backendless.push.BackendlessPushService$4.handleFault(BackendlessPushService.java:486)
at com.backendless.async.message.AsyncMessage$FaultHandler.handle(AsyncMessage.java:83)
at com.backendless.async.message.AsyncMessage.handleCallback(AsyncMessage.java:41)
at com.backendless.core.AndroidCarrier$1.handleMessage(AndroidCarrier.java:37)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6682)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)
Solved in slack.
By the way, proceed to use the Firebase Cloud Messaging, because all deprecated methods will be deleted in next version of sdk.
how to move to fcm??? where the documentation?
Hi Zeev, we made all the changes in the docs. I am waiting for the latest build of the SDK to hit the public maven repository and as soon as it happens, the docs will be updated on the website.
the sdk is out 
need the doc to understand
It should be version 5.2.1 of the SDK. I do not think it is out yet.
Please use Backendless SDK for Android 5.2.1.
The updated documentation is available at:
https://backendless.com/docs/android/push_push_notification_setup_androi.html
Regards,
Mark