I installed an application using Personal Package Archives (PPA). I installed the application by adding the "unstable" PPA, and now I want to switch to the "stable" PPA. So I removed the "unstable" PPA, and added the "stable" PPA. After doing the apt-get update/upgrade, it didn't detect a change, and the application is not getting reinstalled to the "stable" PPA.
How do I trigger apt-get to re-do the install?
Depending on the PPA we may have only installed a single package from there. After having disabled a PPA we can just purge this package to makes sure a previous version will be installed from another source.
sudo apt-get purge <package>
However quite so often a package may need another dependency with a newer version as well, and this version may also be included in the PPA. We therefore may have to also purge any newer or instable dependent package that may have been installed.
To ease this process there is a package ppa-purge which will revert any packages to those installed from the Ubuntu repositories:
