Rare have announced that Forsaken Shores, which is set to be a free expansion for Sea of Thieves, has been delayed by one week. The original launch date was supposed to be 19 September but the new date is set on 27 September 2018.
According to the official blog post, the decision "was not taken lightly", and Rare are aware that the fans will be disappointed with the delay. That said, their reasons for the delay seem to be focused on polishing the content in order to deliver a "stable, polished and bug-free experience".
Rare took the opportunity to also extend thanks to Pioneers, or the testers, who dedicated their time for playing the new content and providing necessary feedback, which ultimately led to unearthing many bugs. The post also mentions "continued support" during the testing week, which could mean that the testing is still going on, but Rare's statement is a bit cloudy in that part.
You can check the official post for yourself and see what kind of context this particular sentence could be in. The statement ended in extended thanks with a wish from Rare to see players in Devil's Roar soon.
While the delay isn't a particularly long one, it could indeed be frustrating for the players since Forsaken Shores contains what the fans craved from day one - more content. The update will introduce the aforementioned volcanic region that will contain new challenges as well as more exploration opportunities.
This will be the third expansion in Sea of Thieves, after the Hungering Deep and Cursed Sails and Rare seemingly have no intention of stopping there. They have announced more free content previously, but microtransactions will make their way to the game at some point "after enough free content" has been deployed.
On the topic of free content, a battle royale mode could potentially be introduced as well, since Rare have previously expressed they would put "a unique spin" on the mode, should it come to Sea of Thieves. Then again, everyone these days claims their games will have a unique spin to battle royale.