cant update upfront from my dashboard

I just updated Fixer but cant update Upfront so I cant do anything with my theme now.
I get this:
"you have successfully updated Fixer. Unfortunately, this theme update isn’t compatible with your current version of Upfront so it’s important that you update to Upfront 1.0 now to keep your website running smoothly."
But when I try to update upfront I got the same popup coming, or through my dashboard: "no source available" Please help with this