The Fortnite 3.5 update was released this morning at 4AM EST and includes numerous changes for both Battle Royale and Save the World. Of particular note is the addition of the Port-A-Fort in Battle Royale, weapon nerfs, a replay system to allow you to rewatch your favorites matches. The Port-a-Fort is a new rare grenade-like item that when thrown creates a portable fort that can be uses for a quick defensive position while on the go.
Source: https://www.bleepingcomputer.com/news/gaming/fortnite-35-update-port-a-fort-new-replay-system-weapons-nerfed-and-more/