It works perfectly. I just keyed it up, set up a course and conditions, and then tried to invite a couple on my friend's list that showed up as in the game. I only set it up for 3 holes as I wanted to merely see if cross platform worked. Not sure if the cross platformers knew what the heck was going on since this is brand new so they rejected my invite, I guess because it was only 3 holes and practice. Then I clicked invite anyone and got lots of tour champions doing the same but about the 4th person to show up - a legend - like myself, accepted the invite for a 9 hole ranked round.
I asked him while the game was in progress if he was playing mobile or PCEA and he said no, he was playing the flash version. Now you may wonder what my screen looked like while playing him. He showed as a default mobile avatar with default apparel.
This update is a big deal.