Metal Gear Online Will Support 16 Players
Metal Gear Solid V: The Phantom Pain's online mode will support 16 players on the PC and current generation console version, but only 12 on PS3 and Xbox 360. This is according to The Phantom Pain's Japanese website.
It's not known if there will be other downgrades in the older generation of consoles, such as smaller maps, similar to Battlefield 3.
Despite Hideo Kojima's plan to leave Konami, Metal Gear Solid V will still be released on September 15th for PC, with Metal Gear Online being a free component.