RxJava 1

At the beginning the project used RxJava 1. That version is no longer supported — please update to the RxJava 2 version.

If you are migrating from RxJava 1 you'll have to use new artifact:

Was:

implementation "com.polidea.rxandroidble:rxandroidble:x.y.z"

Is:

implementation "com.polidea.rxandroidble2:rxandroidble:x.y.z"

There is no migration guide however vanilla RxJava1 -> RxJava 2 guides apply well. You can read more about differences here.

Note — Prior to version 1.3.0 each failure on BluetoothGatt was effectively closing the connection. From 1.3.0 onwards individual errors will not close the connection if they are not directly related to it. This change does allow to retry operations (i.e. after Android will establish a device bond).