PHP 4.4.2 (cli) (built: Jan 26 2006 13:52:30)
Copyright (c) 1997-2006 The PHP Group
Zend Engine v1.3.0, Copyright (c) 1998-2004 Zend Technologies
Nutsmail says that it take the squirrelmail requirements...
* UNIX/Linux or Windows (UNIX/Linux version may be more functional)
* An IMAP server which supports IMAP 4 rev 1.
* Web server with PHP installed (for example Apache httpd)
* You need at least PHP 4.1.2. If you are using PHP 4.1.2 or 4.1.4, please upgrade to the latest version ( >= 4.1.2.11, >= 4.1.4.1 final).
* Perl installed on the system. (If you don't have Perl, SquirrelMail will work fine but it's very helpful for the initial configuration. Alternatively, you can manually edit the configuration files.)
* Unlike many PHP applications, SquirrelMail does not require MySQL or other database type.
* If you use MySQL for the address book or for preferences, note that Pear DB library is required to be installed and available in the include path.
* Aspell or ispell installed if using the SquirrelSpell plugin, For UNIX/Linux see:
http://aspell.sourceforge.net/ or for Windows, see:
http://aspell.net/win32/
* Japanese language support: PHP must be compiled with the --enable-mbstring option for SquirrelMail to read and write Japanese emails. Each user must also set their language option to Japanese.
* PHP mbstring extension is required for translations that use multibyte or not ISO-8859-1 character sets. Without mbstring extension interface will remain usable, but some i18n features and fixes won't be enabled.
* PHP XML extension is required, if digest-md5 authentication is used.