Evidence recently started mounting that something interesting was afoot in Fortnight, a game developed by Epic Games that is available for both Xbox One and PS4. The first indications of cross-play between the Xbox One and PS4 for this particular title came when PS4 gamers noted that there were players running around in their games that had spaces in their online usernames.
The PS4 doesn't allow spaces in usernames, only underscores or other characters. A bit of sleuthing by some of those users turned up the same exact players and usernames active on the Xbox One version of the game. More definitive proof came when a father and son duo played the game together using an Xbox One and a PS4 in the same room.
Shortly after that proof landed, Epic Games stepped up and stated that indeed PS4 and Xbox One gamers were able to play against each other in the same matches. Sadly, the cross-play action wasn't done on purpose, it was some sort of configuration error that dropped the wall between the two gaming worlds for a brief time. Epic Games told Ars Technica, "We had a configuration issue, and it has now been corrected."
Microsoft has been very clear that it is trying to get Sony to agree to allow gamers on each console system to play against each other in the same games. So far Sony has refused. Before Epic Game made this configuration error, it was easier for gamers everywhere to rationalize that making cross-play happen is hard. This configuration error proves definitively that the only thing stopping cross-play right now is Sony.
Microsoft said, "We're talking to Sony [about cross-play], we do partner with them on Minecraft and of course we would like to enable them to be part of that; one community, to unite gamers. So we're talking to them and we're hopeful that they'll be supportive of it."
Microsoft does currently have cross-play support for Minecraft with Nintendo proving that it is willing to let gamers play together even if they don't buy Microsoft hardware. As close as we have to a reason Sony is standing in the way of cross-play came from PlayStation marketing head Jim Ryan this summer talking about Minecraft cross-play.
Ryan said, "We've got to be mindful of our responsibility to our install base. Minecraft—the demographic playing that, you know as well as I do, it's all ages but it's also very young. We have a contract with the people who go online with us, that we look after them and they are within the PlayStation curated universe. Exposing what in many cases are children to external influences we have no ability to manage or look after, it's something we have to think about very carefully.
"It's a commercial discussion between ourselves and other stakeholders, and I'm not going to get into the detail of that on this particular instance," Ryan added. "And I can see your eyes rolling."