RAS Componenents an different Versions

i everyone,

we are currently running Parallels RAS 20 in production and are planning our upgrade path to version 21. One question we have is about component compatibility, specifically the HALB appliances.

Is it supported to upgrade only the HALB component to version 21 while the rest of the farm (connection brokers, gateways, agents, etc.) is still running on version 20? In other words, can we run a mixed environment where HALB is already on 21 but the main RAS farm is still on 20, or must all components (including HALB) always match the same major RAS version?

If this is not supported, what is the recommended sequence for upgrading HALB in relation to the rest of the RAS components when moving from 20 to 21 (e.g., brokers first, then HALB, then agents, etc.)?

Any official guidance or experience from similar upgrades would be greatly appreciated.

Thanks in advance!