Taking cues from playground battles across the world, Fortnite is adding a stink bomb to its roster of cartoon weaponry. The new weapon will cause continuous damage to anyone standing within its radius (you know, just like real life).
Additionally, patch 4.4 introduces Final Fight, a Battle Royale in which teams of 20 will fight to have the most players standing at the end of a round. The storm circle is less restrictive in this mode, necessitating teams really hunt each other.
Finally, the patch fixes a number of bugs and performance issues.
Source: Game Informer Fortnite Adds Stink Bomb And A New Battle Royale Mode