So, I just installed the update (Mac M1), and i'm getting the mentioned error. My previous version was 2.4.2 and there were no issues (and i'm able to use the previous version)
Looks like you may be running an old version of the Sim with a game that was built using the 2.5 SDK. Look in your ~/Developer folder and delete the old SDKs so the old Sim isn't launched incorrectly.
Thank you, yeah I had to remove the old Playdate Simulator.app from the Applications folder and move the new one there, since i'm using the terminal to open the builds.