The version discrepancy of VRAs in paired sites can be up to one major version apart. Zerto will prevent a ZVM upgrade process that might result in a version discrepancy that is more that one major version.
For example: If we have site A that is running version 7.0 and site B that is running version 7.5, we will not be able to upgrade site B to version 8 until site A is upgraded to version 7.5

Root Cause

An outdated VRA version running on one of the local VRAs or its peer sites. 


Upgrading the ZVM will fail with an error -  'Not All VRAs are compatible'


Local VRAs 

First, validate that all of the local VRAs in the 'Setup' tab of your ZVM GUI are showing as 'Latest'.

Peer VRAs

VRAs in the paired sites (all paired sites to the ZVM you are upgrading) have an effect on the upgrade - so they should be upgraded to 'Latest' as well.

Unlike the ZVR upgrade, upgrading VRAs will have an impact on replication.