Two parts to this - first that I was using the wrong version, but also the wrong upgrade code for the bundle. Those are both fixed now, but it does mean that both 3.5.0a1 and a2 will need to be manually uninstalled.

It is possible to add a list of the upgrade codes that have already been released and remove those too, but since they are only alphas I'm not worried about requiring manual uninstall of those versions.