FYI to anyone having issues loading Universal-Updater and getting an "Invalid UniStore" error: Dynadot's DNS is having issues and causing
Universal-DB to be down. I've switched over to Cloudflare's DNS as it sounds like they're more reliable so everything should be back to normal soon, but DNS changes take a while to propagate so it may be down for a bit.
I think once you're able to access the Universal-DB website it should work if you reload Universal-Updater, if not then go to settings -> Select UniStore... -> + -> Universal-DB to add it.
Edit: I can confirm it's working again for me on Google and Xfinity's DNS servers, not Cloudflare's yet though funnily enough, so it should be good just might take a while to fully propagate. I think they usually say 24 hours or so at max.