Not sure if it brings new content, but an express update is being deployed on April 7 in Fortnite. It's likely to be a patch designed to fix some major bugs, such as the Grenades bug — which forced the explosive to be removed from the arsenals.
As indicated in the release, a maintenance period will be required before taking advantage of any new content. As a reminder, a Doomsday event is in preparation in the game files, but it seems unlikely that it will happen following such a small and unexpected update.