I'm finally downloading a patch right now, but it says March 1, 2021 security level with a few other improvements with a download size of 923.77MB. I'm on Sprint Note 10+ Unlocked.
Edit - I guess that was also my OneUI 3.1 update because it says I am now on that after the update.
Since I last posted, I now have the April security update.
I'm not minding 3.1 on my tablet, but I have it set up differently than my phone. There are quite a number of phone apps I don't put on my tablet, which I use primarily at work for media during the slower hours.
I think I could be happy with it if they'd just give me more control over the icon grid numbers, and dock, folders and Google widget settings. Oh, and let us use icon packs too. I have to say I do love my Nova lol.