Cross Platform on PS4

I've been playing cross platform with my son for about a year.  I'm on PS4 he's on an IPad.  Since the most recent update we can no longer play.  I keep getting info that ps4 doesn't support cross platform play but we did it for over 10 months and it's an option so that seems weird.  I can search for him and he comes up but we are unable to join.  Both have accounts with microsoft.  Please help.