Officially announced yesterday, update 11.21 was deployed during the night in Fortnite. It was via the Fortnite Status Twitter account that the information was confirmed. Epic Games announced that the patch required downtime during which the game would be unavailable.
Some dataminers tend to lean towards a massive arrival of new content next week, on the occasion of the 11.30.
In addition, Fortnite's official social networks only seem to announce various bug fixes for 11.21 at the time of writing.