Vault not compatible after Update to 21.6

Upgrading the vault fixed it, but what if I want to go back to 21.5 if something doesn't work? Am I right, that after upgrading the vault needs 21.6 or higher?

Vaults that are online are automatically upgraded when M-Files Server is updated, offline vaults need to be manually upgraded. Upgrading a document vault makes it incompatible with older M-Files Server versions: www.m-files.com/.../Operations_Upgrade.html

There can be circumstances where the automatic upgrading of online vaults are interrupted by some automated nightly server routine like backup or updating other software on the server. This will lead to a situation as described. You can avoid this by setting the allowed time for M-Files updates to not coincide with other maintenance routines. Should it happen anyway it is a simple task to upgrade vault from Admin.

Your backup plan should give you the option to restore the vault as it were before the update. You can request a link for older versions of M-Files if you need to go back. You would have to remove M-Files from the Desktop and Server, install the old version and restore the vault from backup. Fortunately, that has not been necessary in my time working with M-Files although there have been a few cases with small errors in new versions. Any major errors are generally fixed within a few days.

There can be circumstances where the automatic upgrading of online vaults are interrupted by some automated nightly server routine like backup or updating other software on the server. This will lead to a situation as described. You can avoid this by setting the allowed time for M-Files updates to not coincide with other maintenance routines. Should it happen anyway it is a simple task to upgrade vault from Admin.

Your backup plan should give you the option to restore the vault as it were before the update. You can request a link for older versions of M-Files if you need to go back. You would have to remove M-Files from the Desktop and Server, install the old version and restore the vault from backup. Fortunately, that has not been necessary in my time working with M-Files although there have been a few cases with small errors in new versions. Any major errors are generally fixed within a few days.