I've just completed a fresh install of 5.0 from the ISO on the website, but am unable to update/upgrade packages.
Trying to run
sudo apt update, or install anything from the AppCentre both result in the following error:
E: The repository 'http://packages.elementary.io/appcenter juno Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
This seems to be the same issue as in this page: Juno sources - no release file
I'm about to try following those instructions to resolve it, but thought I'd post an update that this is still an issue. Unable to install software on a fresh install seems like a rather critical bug to fix from a user experience point of view...