I have recently asked about how to upgrade ghostscript
to a version that is available on 15.04 but not on 14.04LTS (which I have). On this site there are numerous almost identical question regarding different packages, a few examples include:
- How to upgrade to a newer version of a package than is available in the repository?
- How to upgrade a single package using apt-get?
- How to upgrade to a later version of Remmina than is in Repository
- Upgrade tmux from 1.8 to 1.9 on Ubuntu 14.04 (on Stack Overflow)
So I thought it would be very useful in general to know: is there a general, automated way to upgrade a package, including all its dependencies, to a version that is newer than Ubuntu's repos? Is this more easily done if the newer version exists in more recent Ubuntu releases?
The broad answer to your question is no. As A.B. wrote in the answer you reference, installing software versions ahead of the official repositories will mostly likely to result in unmet dependencies, breaking things along the way.
There are two basic ways to upgrade software relative to the versions provided in the official repositories (none of them automatic):
Compile the software yourself (and all its dependencies).
Install the software from a third party PPA that may provide a more recent version.
Note that in both cases however, it is very possible this software becomes unusable after a system upgrade (e.g. from 14.04 to 15.04).