What is new in the LG Display OLED EVO panels?
1. instead of a Blue/Yellow-Green/Red/Blue sandwich structure, the new panel has a Blue/Green/Yellow-Green/Red/Blue structure (as already mentioned here)
2. LG switched the supplier of the emitters from Idemitsu Kosan to DuPont, at least for the blue emitter; DuPont's blue emitter uses deuterium atoms instead of hydrogen which are more efficient at converting current to light
All this is according to
this forum post (this forum is usually quite detailed when it comes to the tech behind TVs).
My suspicion regarding the switch from a Japanese supplier to a US one is that it is also partly due to the frictions between Japan and Korea that
flared two years ago, with Japan imposing export control restrictions on chemicals used by the Korean electronics manufacturers as a retribution.