Here's is how I updated gpans' squirrelmail package with the current version (1.4.13).
# cd /usr/share
# wget 'http://superb-west.dl.sourceforge.net/sourceforge/squirrelmail/squirrelmail-1.4.13.tar.gz'
# tar -xvzf squirrelmail-1.4.13.tar.gz
# rm squirrelmail-1.4.13.tar.gz
# rm squirrelmail-1.4.13/config/config.php
# rm squirrelmail-1.4.13/config/config_local.php
# ln -s /etc/squirrelmail/config.php squirrelmail-1.4.13/config/config.php
# ln -s /etc/squirrelmail/config_local.php squirrelmail-1.4.13/config/config_local.phpThen changed the below files to include the Ensim virtualization hack (See attached diff patch):
squirrelmail-1.4.13/functions/prefs.php
squirrelmail-1.4.13/functions/global.php
squirrelmail-1.4.13/src/redirect.php
squirrelmail-1.4.13/src/login.phpFinally, I moved the old squirrelmail folder and symlinked to the new one.
# mv squirrelmail squirrelmail-1.4.8-1.1.ensim.ct
# ln -s squirrelmail-1.4.13 squirrelmail