What even is second revised? When did that come out?

Yes, everything in OG 2nd edition is basically compatible with the remaster. While you should generally use the updated version if available, the mechanics are so lightly tweaked for the most part that you will have no issues.

For organized Society play, you are allowed to use anything from the original 2nd edition that hasn’t been republished in a remastered version yet.

When did that come out?

Release Date: Nov 15, 2023

Thanks. I was looking through my pdf and thought it looked compatible, but not having played yet was not totally sure.

2E Remastered started coming out in November 2023. Mechanically it is a very lightly polished version of 2E. It was created as response to WotCs OGL shenanigans and mostly consists of removing and replacing anything that their lawyers thought might be construed as covered by WotCs OGL bullshit and then released under the new ORC license.

To add a little more detail, the primary differences are:

1. A bunch of things got renamed on the advice of lawyers or to make things clearer. e.gs Magic Missile ->Force Barrage, Spell Level -> Spell Rank
2. Alignment got removed and replaced with Sanctification (holy or unholy), Anathema and Edicts
3. Wizard Schools got reworked for lawyer reasons
4. Witch Class got some reworking
5. Lots of ancestries, monsters, and items got renamed, sometimes with small changes, for lawyer reasons. E.g Dragons are no longer color coded, but more based on different mythologies and archetypes.

Edit: Paizo’s overview of the changes is available at https://downloads.paizo.com/RemasterCorePreview.pdf