It looks like the Skyrim Special Edition beta patch 1.1.51 (released as a test branch on 3 November) is now live for all players. Steam is currently download a 950mb patch, though there isn’t yet official word on changes from Bethesda.
Assuming it is the beta patch going live (and I don’t see what else it’s likely to be, really), then it’s going to be supplying the same fixes and changes as that release. That is to say updating some of the overly-compressed audio, “performance and optimization improvements,” and addressing some saves erroneously being marked as ‘modded’ when they are not.
Here’s the old beta changelog, except this Skyrim Special Edition patch to be roughly along these lines.