I've seen a couple of reports (on other builds, it's nothing Slice specific) where people aren't seeing 8.0.0 in the lists of available manual updates. This can only be an issue with mirror servers as the JSON file queried by the settings add-on is 100% correct on our servers.
I see, Thanks; Will the mirror issue be resolved at some point, so wait for the update to show in the list of available updates? (since I'm not in a rush)