Ignorant question: For CF2021, I want to test a cf upgrade process, but be able to roll it back. Is it valid to save off a copy of the ColdFusion2021 directory, and if I want to roll back, stop cf and put my saved copy of it back where the old one was? Is there a better way?

I recently did that successfully.

Thanks Jakob. Anyone know if this is the "official" way?

You should be using VSS or Virtual Machine style backups. Your Software "Code" should sit on all one "DRIVE" that is not attched to the "App" coldfusion instance. You can spin Up another COLDFUSION box, rettach the code. That is the "ENTERPRISE" way. The smaller department way would be to "Backup your VM" Do whatever "Restore your VM". If you are using physical servers for what ever reason, trade VM for BACKUP, though you really, really should be using VM or container tech.

The "server" is actually a VM, but sysops manage those, not dev, and I don't want to get into having them restore the whole VM. An unofficial copy is good enough.