Updating to latest nano text editor

I found a workaround on this by modifying /etc/apt/sources.list

from

deb http://mirror.debian.org/debian jessie main contrib non-free
deb-src http://mirror.debian.org/debian jessie main contrib non-free

to

deb http://mirror.debian.org/debian testing main contrib non-free
deb-src http://mirror.debian.org/debian testing main contrib non-free

Removed nano 2.2.6 by apt-get remove nano then apt-get update

Finally install nano by apt-get install nano

Check version by nano -V

I'm running nano version 2.7.0 now

I was logged in as root while doing this so I needed to cp /bin/nano to /usr/bin/nano so I could launch nano directly.

Note: Do not forget to revert your /etc/apt/sources.list

Include as Bryan Cerrati pointed out:

Installation using .deb files.

dpkg -i nano_2.7.1.deb

Get nano at Debian GNU/Linux binaries stable | testing | unstable

Note: Make sure you properly select the appropriate architecture for your machine.