I've a 60+ solution with 8 or so distinct packages in our local repository (network share). When I want to upgrade the packages to the latest prerelease version, I issue:
update-package -includeprereleases -safe -source \\my\share
At the beginning I thought I was doing something wrong, but now I think there is something misplaced, because around 70% of the projects get updated with the latest version of the packages, and the rest, remain with the original version.
For the time being, I have a powershell script that uninstalls and installs all the packages for every project. Slower for sure, but I don't need to worry about tracking down orphan updates.
Anybody else has run into this?