What is the best way to install the e-book manager Calibre? The version in the Ubuntu repositories (available through Muon) is very much out of date. There is a PPA, but the latest Calibre (2.x) seems to require Qt5 libraries, so the maintainer warns against installing it on Ubuntu 14.04 Trusty. I am wondering whether it is safe to install it on Netrunner 14.1, since that has some updates from Utopic?
The latest version of Calibre is in this PPA
https://launchpad.net/~n-muench/+archive/ubuntu/programs-ppa
But there are two other PPAs of the same maintainer with older versions, which may be safer to install. I am a bit confused as to which one to use.
https://launchpad.net/~n-muench/+archive/ubuntu/programs-ppa2
and
sudo add-apt-repository ppa:n-muench/calibre2