After rolling out to Verizon customers just last week, T-Mobile and Samsung have begun rolling out Android 8.0 Oreo to the Galaxy S8 and S8 Plus (via Android Police). The update ships with the February security patch on board and weighs in at around 1.5GB.
With Oreo on the S8 and S8 Plus, you get access to features such as picture-in-picture, autofill, improved speed, better battery life, enhanced security, a new UI called Samsung Experience 9.0, App Shortcuts, and more. You can learn more about the update in our Galaxy S8 re-review.
Be sure to jump on Wi-Fi before installing since the update could eat up your cellular data pretty fast.