http://www.pcgamer.com/playerunknowns-battlegrounds-beats-dota-2s-highest-concurrent-player-record/

PlayerUnknown’s Battlegrounds’ unstoppable rise continues, with the game hitting yet another milestone today. The massively popular battle royale shooter has now broken Dota 2’s record for highest concurrent player count on Steam. 

Yes, Dota 2’s 1.29 million record has been shattered, with PUBG hitting 1.3 million concurrent players. That’s the most people playing at the same time any game on Steam has boasted.