Relative date filters (ending.month changed?)
It looks like the (default) options for relative comparisons on dates have been slightly improved (or at least, that would have been the intention). You wouldn't normally want to break a site that was making use of the old ones, so I wouldn't describe that as an upgrade error. Whether the difference is important would be up to you. If you're not using the old ones, then you could update, or even add the new ones.

You can do that with the web interface at: Administer -> System Settings -> Option Groups, and choose Date Relative Filters.

These are intended to be configurable, so the preferred behaviour for upgrades is to not break any existing configuration.