Document upgrade and downgrade processes

[zamazan4ik]

Hi.

After reading the documentation it is not clear for me, how upgrade and downgrade processes should be performed over the solution. Could you please describe somewhere in the documentation:

• How to upgrade k8up to the newer version (hopefully with no downtime)
• How to downgrade k8up to the older version (hopefully with no downtime)
• Maybe some compatibility policies and notes between versions

Thanks in advance!