I've upgraded a lot of stuff I wish could be downgraded to fix new bugs or unwanted features. Altium is a great example: doesn't care what version of software you're running and will tell you if a new feature can't be handled in an old version (obviously, with an embedded device it can't do that, but it can ignore the new data). Altium 09 can be used to view Altium 23 documents perfectly well, despite the features introduced in the intervening 16 years.
I have similar software, and I love 'em. For the user they are pain free, and these things should be designed for the user, not the developer. In contrast, there is stuff I can't allow to be updated because there is no way back, and I hate 'em.
pfSense is middle of the road. You can export settings, update (or install somewhere else) and import. The worst I've had has been the Ethernet interfaces changing names, so the low level network IDs have to be frigged about with. But the bulk of the settings have been fine. But look at Tweetduck - minor update and it can't import settings from the previous version. Another one I used to not allow to update (pointless now since it no longer works, thanks to Musk).