They did not say. They referred to it as an older thing.
I can only speak for a Samsung Galaxy Tab A running 7.1.1 which smoothly brings me through the login doors and then shunts me back to my device home screen halfway through that panning motion,
and a LG Rebel 4 running 8.1.0 that seems to lag so fiercely upon successful login (the moment the options gear appears). One in about 20 tries will take me to the playing board and one in about fifty tries actually gets me all the way to the menu where it suffers extreme lag (small particles in motion and changes in shadows/lights indicating whether the game has crashed/frozen) locks the game down entirely.
It’s interesting that the bad device can actually get to main menu before FREEZING but the far superior device simply CRASHES the game entirely and sends you away.
I also lack the skill to fully interpret the post, but someone is at least posting some solid stuff for Blizz to scratch their heads at over here: