I had a weird Java error appear after updating to Fabric. It turned out the problem was - I forgot to remove the crashlytics.jar
from the libs folder and there were still a few libraries there and the whole folder was getting compiled so when Fabric got added through aarr
file, I ended up with 2 copies of the library, which created the problem.
The initialization for Fabric is a little different now too.
Fabric.with(this, new Crashlytics(), new Twitter(authConfig), new MoPub());
or
Fabric.with(this, new Crashlytics());
if you only use Crashlytics