Samsung continues to update more devices to One UI 3.1 — here's the complete list - Android Police

One UI 3.1 has been rolling out to older Galaxy devices quickly in the last few months

Over the last few weeks, One UI 3.1 has arrived for several mid-range devices and some T-Mobile variants

Although some features will remain exclusive to the S21, this is still a substantial update, especially for devices that were updated straight from One UI 2.5