Raid Revenge isn't working; Please post version, build, & OS in comments to help find common link

Running Version 1.12.5, Build 733 with Android OS and no updates available. Every player I attempt to revenge who’s playing on a different app version (stated at the bottom of their profile card) fails with the message “OPPONENT UNAVAILABLE. You cannot attack (insert name) right now. Reroll?” even when they have been offline several hours. I apologize to Rigwald the Wolven King for using him in the example, but with such a killer team, I didn’t think he mind.

This is common. Happens every time a new version is released. It will sort out when they drop support for prev version.