Mortal Kombat 11 Cross-Play Confirmed For PS4 And Xbox One
 

NetherRealm has issued a new [Only registered and activated users can see links. Click Here To Register...] update that appears to include a significant new feature--though it is nowhere in the official patch notes. The version 1.13 update history when viewed on PS4 has a note that it "Add cross-play."

MK11 December 12 Patch Notes

General Gameplay Adjustments

Fixed an issue causing several Krushing Blows to do slightly increased damage
Added an Newsletter Subscription option which rewards players with a Raiden Announcer Voice for signing up
Fixed an issue that was causing Nightwolf, Sindel, & Terminator Augments to not work as intended
Kombat League / Online

Reduced the Kombat League Point Cap that a player can lose in a match to 50

Towers of Time

Fixed an issue with certain attacks killing the opponent at the same time a modifier activates during an Endurance Match causing a long delay before the next opponent appears
Fixed a rare issue that could cause the camera to get out of bounds when a Fatal Blow or Krushing Blow occurs while the Ice Totem is active

Character Specific Adjustments

Baraka - Blood Lunge’s Krushing Blow works correctly again in all situations