I have updated my Calibre Debian repository to include packages of the current Calibre 3.1.1. As with the previous packages, I kept RAR support in to allow me to read comic books. I also have forwarded my changes to the maintainer of Calibre in Debian so maybe we will have soon official packages, too.
The repository location hasn’t changed, see below.
deb http://www.preining.info/debian/ calibre main deb-src http://www.preining.info/debian/ calibre main
The releases are signed with my Debian key 0x6CACA448860CDC13