https://www.gamespot.com/articles/sea-of-thieves-update-the-hungering-deep-out-now-o/1100-6459260/

Avast ye, matey, for Sea of Thieves' new content, The Hungering Deep, is now available. The free update adds a plethora of new features, including a speaking trumpet to alert other players of your presence, ship flags, a drum to add percussion to chanties, cosmetics like tattoos and scars, and more. In addition to adding content to the game, The Hungering Deep also fixes issues like pop in, server stability, and CPU performance when loading objects.

More importantly, Sea of Thieves finally gets something that resembles a story. As stated on the official The Hungering Deep page, you "follow the trail of riddles and rumours to piece together what happened to 'Merry' Merrick, the proud owner of a pair of matching peg legs." There isn't much to go on, but you might be able to find a group of adventure-seekers called the Bilge Rats in taverns who may provide more details. Unfortunately, this new story content is "time-limited," so gather your crew, raise the anchor, and set sail to see if Merrick is in Davey Jones' locker or not. Head over to the Sea of Thieves page to read the full patch notes.