I’ve been running MIAB for a few years now, and never had trouble with upgrading to another version. (I run a reasonably standard MIAB box but self-hosted.)
I have kept a record of the (minor) tweaks I made, so I can check/recreate them after upgrades.
If you’ve got the current backup copied to another machine, the restore process is fine.Should the worst come to the worst, you wouldn’t be down for long