I can no longer update game on my Nexus Tablet

For years I have played this game on my Nexus tablet.     When an update was attempted, the Play store said my device was not compatible without any specific reason.

I have plenty of storage and my OS is 6.xx which are both beyond what is mentioned in the 'mobile requirements'.

Tech support is clueless.

Does anyone know how to find a real reason a long running device is no longer compatible?