Yep, you read that title right! Here's the XBox announcement:
A Letter from Chris Charla: [email protected] Updates and GDC - Xbox Wire
Here's a commentary about it:
Xbox Live now supports cross-platform multiplayer with PS4 | TechCrunch
At this point, there’s very little difference between the Xbox One and the PlayStation 4. But there was one key differentiating point. Xbox gamers could only play with Xbox and PC players as Microsoft was restricting access to the multiplayer component. Microsoft just announced that game developers can now create cross-platform multiplayer modes that work with other consoles and operating systems.
So it means that the next Call of Duty or FIFA could feature a multiplayer mode that works with both Xbox and Playstation gamers. It just depends on developers now.
Microsoft has historically restricted cross-platform play as the Xbox Live was the first successful multiplayer network for consoles. The PlayStation Network only appeared with the PlayStation 3.