I tested the new package v5.0.3-1 from Debian unstable on x86_64 systems with Debian unstable, Bookworm, Bullseye and even Ubuntu Focal (GitHub actions runners), and it works very well on all of them. I tested the "ocs-sr savedisk" command, using some different command-line options, compression methods and such.
Probably it would be even possible to provide this version via Bullseye backports at a later time?
However, many thanks for the update, this especially allowed us to remove some nasty patching to hack loop device support into the old version.
Best regards, Micha