db2 - Downgrade of upgraded instance and database?

Question

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.

1. During installation I have got error about incompatible libraries, so it was forced to use db2rmln command to remove Linux links to libraries.
2. After install it was required to upgrade (not update!) instance and I did it with: ./db2iupgrade
3. 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?

Answer 1

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.