The hotfix patch for the Total War: Warhammer 2 Mortal Empires campaign has left beta today, and is now live for everybody. Those who’d been using it in beta through the opt-in method can now switch back to the main ‘build’ branch.
For people who don’t know, the hotfix is primarily intended to reduce the severity of the Chaos Invasions in Mortal Empires. Prior to the patch, they would show up early, in force, and head straight for the player’s faction without really stopping on the way. The patched version should address this in a few ways: the Chaos stacks will show up later in the campaign, and other factions start at war with them (so they shouldn’t all come directly for the player).
In addition, Lizardmen and High Elves will now get the ‘Shield of Civilization’ trait, making them band together with the other ‘good’ factions when the main Chaos Invasion hits. The patch fixes some other issues in Mortal Empires and Total War: Warhammer 2; you can read the full set of notes here. I don’t think these have changed from the beta version.
To guarantee that you’re seeing the effects of the patch, you’ll need to start a new Mortal Empires campaign. But if you’re at a fairly early point in an existing game (prior to Chaos showing up) then you might be okay to just continue.