Android apk file rename Crashlytics task failing

I am configuring Jenkins job for android project, we have crashlytics integration. Before the build is picked up by beta I am changing the file name to have more info about the build no and buildenvironment in the format below

app-Buildno-BuildEnv.apk

After the file name change crashlytics is giving error and build is failing.

WARN - Crashlytics halted compilation because it can't find the specified file: /home/jenkins/androidworkspace/<>/app/build/outputs/apk/app-debug.apk :app:crashlyticsUploadDistributionDebug FAILED

I am using gradle build system. And I have added the renaming of the file and crashlytics task as a post build action.

I want crashlytics to pick up the new apk and not look for "app-debug.apk". The changed filename exists in the same path as app-debug.apk.

Thanks, P