https://www.gamespot.com/articles/fortnite-update-601-out-now-with-new-item/1100-6462222/

Season 6 of Fortnite is underway, and now developer Epic is readying the second update of the season for its popular battle royale game. Patch 6.01 is slated to roll out for all platforms--PS4, Xbox One, PC, Nintendo Switch, and mobile--on Wednesday, October 3, with downtime for the update scheduled to begin at 12 AM PT / 3 AM ET / 8 AM BST. [Update] Downtime for the latest Fortnite update is over and the new update is available. You can see everything added and changed in the Fortnite v6.1 patch notes.

As usual, Epic hasn't provided an estimate of how long downtime will last, but previous maintenance periods have typically run for an hour or two. Likewise, the developer hasn't dropped any hints as to what new content players can expect from the update; usually, Epic teases the arrival of a new weapon in Fortnite's News feed, but as of this writing, the feed has no mention of one.