Update: It looks like T-Mobile is releasing a newer update for the Galaxy S9+ that brings the April patch, while the ones listed on the carrier's website are older updates that included the March 2018 patch. The build number is G965USQS2ARD3, and it's unclear if the same update is also rolling out to the regular Galaxy S9.
Original story: It looks like the April 2018 security patch has finally debuted on one of Samsung's flagship phones. T-Mobile's Galaxy S9 and Galaxy S9+ are currently receiving a new update that includes the latest security patch. G960USQU2ARC6 and G965USQU2ARC6 are the build numbers for the Galaxy S9 and Galaxy S9+ updates respectively, and T-Mobile says the update also includes “various bug fixes.”
T-Mobile pushes latest security patch to the Galaxy S9
This is the first software update rolled out by the magenta carrier for Samsung's 2018 flagships, and the rollout began on April 13, which means it should be available for all Galaxy S9 and S9+ owners on T-Mobile at this point. To download the update, open the Settings app on your phone, tap Software update, followed by Download updates manually. And if you're wondering what the April 2018 security patch offers, you can check out this link for all the details. A short version: the patch fixes seven critical vulnerabilities in Android and eight vulnerabilities that can only be taken advantage of on Samsung's software.
Got the update on your Galaxy S9 or S9+? Let us know in the comments if you see anything new or different after the update has been installed.
