Looks like Sony has pushed an update to the PS3 to improve performance and the update also includes an update for the Blu-ray player so it’ll be able to play newer Blu-ray movies!
See RPCS3 Tweet below for the changelog
PS3 System Update 4.87 has just been released (3rd December 2020)
– Updated blu-ray keys for new movie releases
– Minor security fix
You do not need to reinstall firmware on the emulator to keep using RPCS3 if you already use 4.86
— RPCS3 (@rpcs3) December 3, 2020
So make sure to update your PS3 if you’re still using it!