1.5.2svn (2007-05-30) can't handle active session in different location.
Login page breaks with
Fatal error: Call to undefined function getpref() in /some-path/squirrelmail-devel/include/init.php on line 610
How to reproduce
Create two SquirrelMail installs on same web site. For example, http://www.example.org/squirrelmail-stable and http://www.example.org/squirrelmail-devel. Make sure that you don't have older squirrelmail-devel session cookies. Log into squirrelmail-stable. Don't signout on squirrelmail-stable and try logging into squirrelmail-devel