Debian 9817 Published by has released Nginx 1.4.5 packages for both Debian 6 and 7

Nginx 1.4.5 has been released on February 11th 2014, fixing 7 bugs. More info in the changelog.

As a consequence, Dotdeb’s packages of Nginx 1.4.5 are now available for both Debian 7.0 “Wheezy” and Debian 6.0 “Squeeze” (amd64/i386). Pagespeed and some more modules have been updated, dependencies have been reviewed and proxy settings have been improved (all this according to the Debian Sid changes).

As usual, if you want to know which module has been included in each Nginx flavor, you just have to look at this document.
  Nginx 1.4.5 for Wheezy and Squeeze