4.2 will be the next stable release. 4.1 is the development branch for that release.
So, until 4.2 is finished, there are only 4.0.x versions (current stable) and 4.1.x versions (development).
You can check here if you like, as "this" is the list of packages for all the PPAs.
Now, if you want to update to 4.1.x pre-4.2, that's different... follow the instructions "
here" and select one of the 'master' repositories.