The 1.20 version of Final Fantasy XV is now available for PlayStation 4 and Xbox One and the patch comes with a bunch of new features, including character swapping. The patch came out on December 12th just ahead of the release of the DLC expansion known as Episode Ignis which was released a day later.
As the official site says, the free update includes the conclusion of online timed quests and the introduction of online timed quests, compatibility with Episode Ignis, music tracks from that episode and the multiplayer expansion Comrades and some bug fixes. But the most important feature comes in the form of character swapping which lets you alternate freely between the different protagonists. Anyone who played the open-world RPG knows that before, you could only play as Noctis, so this is the first time you can assume the roles of Prompto, Gladiolos and Ignis in the main story. To have access to this feature though, you need to activate the respective nodes in the ascension menu and each node costs 20 AP.
More DLC chapters are expected to come out in 2018, so look forward to that, as well as some updates.