T-Mobile's Samsung Galaxy S9 and S9+ updated to One UI

Samsung flagships are usually among the last to receive major
Android updates. Although the international versions of the Galaxy
S9 and S9+ received the Android Pie update in late-December, it’s
only now that the T-Mobile variant of the phone is starting to
receive the OTA notification. The update began rolling out
yesterday brings Samsung’s newest One UI skin over Android Pie. Not
only this, but the firmware upgrade also includes support for RCS,
the next generation of SMS/MMS. T-Mobile’s firmware release notes
also mention support for Band 28 (700MHz) while roaming, general
bug fixes and…

Source: FS – Cell Phones
T-Mobile's Samsung Galaxy S9 and S9+ updated to One UI