It looks like we do have a Fortnite update today and a new gun is available, the Harpoon Gun. As is the norm this chapter and season, there are no Fortnite patch notes.
Epic Games usually update Fortnite on Tuesday, although there have been a number of Wednesday updates in the past. Before any update, Epic announce the time and date of the update the day before, but there was no update announcement yesterday.
However, it seems like Epic have released a Fortnite update today. In a Save the World roadmap blog post, it states that were will be two v11.10 content updates. Content updates require no downtime and are usually released at 8 or 9am ET.