UPDATE: While I was writing all that below, Rare sneakily released full details on next week’s The Hungering Deep content expansion, due on May 29th – so much of the speculation down there is now confirmed.
According to Rare, its “medium-sized” Hungering Deep update (compared to those due later this year) consists of two distinct parts: there’s the quest-like limited-time campaign event, and a bunch of new items and features which will remain in the game permanently.
The permanent stuff comes in the form of the new drum instrument, the new Speaking Trumpet (enabling crews to be heard at a distance and to “find other crews on the same voyage”), plus customisable flags for the top of your ship, so that you might signal your intentions from afar. Additionally, there are new personal customisation options in the form of tattoos and scars, plus, of course, the new (probably megalodon-like) AI threat.
Source: Eurogamer Sea of Thieves' latest update sets the stage for next week's big content expansion