I get this error when trying the Firebase Messaging example from Erel:
B4X:
java.lang.NoSuchMethodError: No virtual method subscribeToTopic
The sub in FirebaseMessaging is called SubscribeToTopics (plural!) and the call in Service_Create is CallSubDelayed(FirebaseMessaging, "SubscribeToTopics") (also plural).
Target API is 26, latest firebase-messaging version 17.1.0 (and all other libs are up to date as well).
Using the latest B4A and compiled in release mode.
Ok, guys. This specific issue was solved for me by doing a fresh install of the Android SDK. So I renamed the folder, downloaded and installed it (It took a very long time to install, so one needs to be patient.) After the install, Pointed the folders correctly in tools configure paths etc. and all is working fine now.