Pidgin 2.7.1 doesn't bring as many changes as 2.7.0 did (which was released about 2 weeks ago), but it does bring something MSN users have been waiting for about 3 years: fix for a MSN file transfer bug.
Until now, Pidgin didn't support direct file transfers with the official MSN client making the direct file transfer very slow. This bug was finally fixed a few days ago and it has been included in the latest Pidgin 2.7.1:
A full changelog for Pidgin 2.7.1 can be found HERE.
To install Pidgin 2.7.1 in Ubuntu, simply use the following commands:
sudo add-apt-repository ppa:pidgin-developers/ppa && sudo apt-get update
sudo apt-get install pidgin
For now, the Pidgin PPA above has only been updated with Pidgin 2.7.1 for Ubuntu 10.04 Lucid Lynx, but older Ubuntu version should also get the latest Pidgin version soon.
If you're adventurous, you can use another PPA which packs Pidgin SVN packages:
sudo add-apt-repository ppa:frasten/ppa && sudo apt-get update
sudo apt-get install pidgin