Nothing crazy, just have moved everything over to being based off of Regolith 1.6, as well as started buildling directly from source here and there, instead of just downloading and extracting 100 .deb packages (there are still a lot of .deb packages as that's the only way to get many of them).
If you're using the AUR or makepkg then this release doesn't matter to you, as long as you're up to date you already have it.
But if you don't want to build anything, just download the tarball, extract it somewhere, then run sudo pacman -U *pkg.tar.zst. And it'll install everything for you.