URP 14 was released with 2022.1.0f1 and there is no What’s New section in the documentation. We use this to determine how to upgrade to the new Unity version. Why hasn’t this been updated?
Maybe there are no new features at all, only bug fixes and internal changes, just a guess. 
If you click through to the 14.0 Changelog at the bottom of the page, that’s where you find out what’s been added, fixed and deprecated. I imagine it’s just an oversight to not have updated that particular page, or perhaps they do that when there’s some big splashy things to talk/blog about.
Per-light soft shadow setting, some upscaling filters, and more options on the bloom effect, looks like those are the main things so far, with cross-fade mesh support coming in the next 14.0 version.
Edit: Oh, and the dates on the Changelog page are slightly wrong, the date on 14.0.2 says 2021 and it should be 2022.