The Metal Gear Solid games span across decades, though not in chronological order. This should clear the timeline up.

Metal Gear Solid 2: Sons of Liberty is perhaps getting the most changes. These include expanded screen settings to include resolution options, the ability to switch cutscenes between their ...

While there's been no confirmation of a Metal Gear Solid 6 on the horizon, it seems unlikely that Japanese entertainment giant Konami would abandon one of its most beloved properties so easily.