The problem of the database structure of home assistant. When you upgrade home assistant from version 2025.3.4 to a subsequent version, you can upgrade normally. The upgraded new version will modify your database structure. Once you run the new version for a few seconds, the database structure will be modified due to the version upgrade. If you use the snapshot function of esxi to switch back to the old version at this time. Then the old version will no longer be in the menu bar with history records, and the history function will not be available at all. Unless you have a backup database. From my understanding, when upgrading a certain version, the database is adjusted to adapt to the new version. So when we return to the previous version through the snapshot of esxi, we also hope to require the database structure to be adjusted to the database structure that suits the needs of this version. Otherwise, sometimes you mistakenly upgrade to a new version, use some functions of the new version and find that it is not as good as the old version and switch back. Because the database changes to the old version, an error occurs. I hope it can be solved. That is, in addition to adjusting the structural organization required by the old version to the current version, each version can also be adjusted from the future version (downgraded versions are all future things for him) to the version that can run normally
I don’t use esxi, but on my proxmox, the database is included in the snapshot.
It is not know on the time of a release what future database changes will be, so it will have to be done post-release and it would be a huge workload to go back and do that on previous releases.