Can't use/open a backuped catalog after installing demo of C1 23

Hi !

I'm using C1 21 with a catalog and a session.

Installed the free demo of C1 23 and had to upgrade ther catalog (with the automatic backup of my catalog).

C1 23 works with no problems, but now I wanted to use my old C1 21 but can't use my backuped catalog/session, because the program states, that I have to upgrade it first, becaus it was created in Version 14.0.2.36 Pro Win.

But I want to use it with this exact version, so why will C1 21 upgrade the catalog ?

Also my old session was converted to Version 16 and can't be used in C1 21 anymore.

Not really happy with this handling of two different versions on one computer an hope, there is an easy way out of this.

Regards,
Martin N.