Why all Keycloak instances must be upgraded at the same time in Keycloak cluster

[Holm]

Hi,

I read the document and it says "all instances must be upgraded at the same time", and it applies for both Standalone-High Availability Mode and Domain Mode

https://www.keycloak.org/docs/latest/upgrading/#running-the-standalone-high-availability-mode-upgrade-script

Is it because Keycloak uses master/slave and has no support for shadow master?

I would like to know the reason so perhaps find a solution to mitigate this issue.

Best,

Holm