Sunless Pathfinder uses the Pathfinder 2nd Edition ruleset (see https://2e.aonprd.com/) as modified by the current errata.
Ascendant campaigns can view previous versions of their pages, see what has changed (and who did it), and even restore old versions. It's like having a rewind button for your campaign.
We've already been saving your edits, so if you
you will have instant access to your previous versions. Plus, you get a 15-day free trial, so there's nothing to lose.