Thanks to jonMEGA in BPN for the heads up.
Release Candidate 2a of the SquirrelMail 1.4.0 series is now available for download! Since RC1 many issues were resolved; please try and test this candidate so we can make sure it's ready for stable release. It's labeled RC2a because in RC2 a serious bug was discovered shortly after its release; RC2 was pulled back and we now released the fixed RC2a.
What is SquirrelMail?
SquirrelMail is a standards-based webmail package written in PHP4. It includes built-in pure PHP support for the IMAP and SMTP protocols, and all pages render in pure HTML 4.0 (with no Javascript) for maximum compatibility across browsers. It has very few requirements and is very easy to configure and install. SquirrelMail has a all the functionality you would want from an email client, including strong MIME support, address books, and folder manipulation.
Download: tar.gz format | tar.bz2 format | zip format
News source: SquirrelMail