Fortnite is currently offline for its weekly maintenance and update period, and when it comes back online in a few hours it'll bring with it a bunch of new content, some permanent and some limited time available.
The first big addition in V5.2 is that you'll now be able to find a double barrel shotgun in Battle Royale mode, offering devastating power at short range.
Battle Royale is also getting a new limited time mode, called Steady Storm. In Steady Storm, the storm never stops moving, and does not feature a safe zone, meaning that camping in a safe spot until the storm zone shrinks isn't an option. You have to keep moving with the storm rather than hunkering down and defending a spot. The storm closes in still, over a period of 15 minutes, and the storm does a stable 10 damage per second throughout the whole match.
For Save the World mode players, there's a new outfit available in the form of Ragnarok, The Dark Viking. The character has an ability called Seismic Impact, which appears to smash into the ground and cause a huge impact below the player.
The update should also apparently improve performance for the game on Switch, by as much as 10% in certain high intensity scenes.
You can read the full patch notes, including a lot of small bug fixes and numerical changes, here.