[Release notes] Suomenlinna 4.3.0

But you did it the way I meant it and it is supposed to be.

Yes, they all use libzypp, which uses libsolv as its dependency resolver.
But it was working fine for a year (and not only for crypto-sdcard, also for Storeman), hence I assume some update of libzypp / libsolv broke it.
Edit: Looking at the dates, that cannot be the case: I detected the change in behaviour mid 2021 on a device still being on SFOS 3.2.1 (from December 2019; the libzypp RPM was updated from v17.3.1 to v17.9.0 in SFOS 3.2.0 in November 2019), so that does not tell any conclusive story.

Still the RPMs created this way will only install on the intended OS releases, but that has to be performed manually for older OS releases.

And it IMO it is supposed to work this way, but obviously needs a proper bug report at GitHub · Where software is built
I think the observations we made here and at Storeman issue #108 are sufficient for this.