I'm no developper, but I would strongly suggest to recompile all your software using Slackbuild for version 12.1 available on
www.slackbuild.org.
First: some Slackbuilds had to be modified from 12.0 to 12.1
Second: I understand (maybe wrongly) that due to new version of gcc, you may run into problem with programs compiled using an earlier version.
On the last point, I may be wrong (someone will correct me), but if you just recompile with 12.1 Slackbuilds, you'll avoid issue.