Q: db2 - Downgrade of upgraded instance and database? So far I have always "upgraded" database using clean install (new Linux install etc) inside virtual machine.
But now I have requirement to upgrade Db2/Linux from Db2 v11.1 to Db2 v11.5 installed on physical machine (not virtual machine).
Existing instance Db2 v11.1 is installed on the machine.

*

*During installation I have got error about incompatible libraries, so it was forced to use db2rmln command to remove Linux links to libraries.

*After install it was required to upgrade (not update!) instance and I did it with: ./db2iupgrade 

*Then migrate database.

I am just wondering in case of some bad luck. Is it possible to downgrade the instance and database from V11.5 to V11.1? Is downgrading supported between two Db2 releases?

A: No, downgrading databases is not supported. Save the pre-upgrade backup and installation media if you want to go back. Obviously, you will lose all data modified since the upgrade.
