A new update has been released for the PlayStation 4 version of Metal Gear Solid V: Ground Zeroes which allows players to upload their save data for use in The Phantom Pain.
The update, version 1.04, lists only two changes: fixes for Russian translations and the new save upload feature. Once installed, you'll find the option in the main menu. As seen in the image below, selecting it explains that it uploads your save to PSN so that it can be transferred to The Phantom Pain. It doesn't offer any further details regarding exactly what carries over, but it reportedly includes Mother Base recruits and costumes. You'll obtain these by downloading your data from The Phantom Pain's main menu.
At least as of yet, the update adding this functionality has not been released on Xbox One. With The Phantom Pain launching tomorrow, September 1, it will presumably be out soon, but Konami hasn't made any official announcements.
Data transfers aren't restricted to the platform you're on, but you are stuck with the platform family you played Ground Zeroes on. In other words, you can go from Ground Zeroes on PS3 to The Phantom Pain on PS4, but you can't go from PS3 or PS4 to Xbox One, for instance.
Importing save data isn't the only thing that sets The Phantom Pain apart from previous Metal Gear Solid games. It also features optional microtransactions, the prices of which were recently revealed.
For more on both games, check out our reviews of Ground Zeroes and The Phantom Pain.