Epic Games have announced when the v8.11 Fortnite update will be coming.
Epic Games have tweeted on the official Fortnite account the date and time for the v8.11 update. The downtime will begin tomorrow, March 20th at 5 am ET (9 am UTC). The full tweet states the following, “Ahoy, Mateys! The v8.11 update is setting sail tomorrow, March 20 at 5 AM ET(0900 UTC)“.
https://twitter.com/FortniteGame/status/1108088295542673408
In a reply to the tweet above, Epic stated that they’ll be updating some of their social services, and there might be some irregularity with your friend’s list and party options until the updates have completed.

We know the update will bring a brand new weapon to the game, the Flinklock Pistol, which Epic teased after the Item shop updated on Sunday. The stats for the gun were leaked by Storm Shield One ahead of time, but it’s possible they’ll be changed prior to the release.
It’s unlikely there’ll be any leaks in this update as there were a handful in last weeks v8.10 update, but if there are, we’ll be posting everything the dataminers find when the new updated Fortnite files are available to download.