An animation for the trash compactor grate was added to the 2004 version and recreated for the 4K.
The new Dianoga eye and blink added in 2004 was redone for the 4K.
The replacement Aurebesh lettering done in 2004 was redone for the 4K with slightly different angles and spacing.
Example of the redone lightsaber flashes.
Redoing the lightsabers in 2004 made Ben’s lightsaber purple in this shot. Redoing them again for the 4K allowed them to avoid this mistake.