Compatible with Apache, Nginx, or any server that supports PHP.

Includes dozens of translation packages to localize the interface. Installation Guide (Quick Start)

Full support for IMAP (Internet Message Access Protocol) and SMTP. Key Features

SquirrelMail is a classic, standards-based webmail package written in PHP. Known for its "no-frills" approach, it was designed specifically to be a lightweight, easy-to-configure tool for managing IMAP and SMTP mailboxes. While many hosting providers have phased it out in favor of modern alternatives like Roundcube, it remains a favorite for system administrators who value low server requirements and pure HTML compatibility. Latest SquirrelMail Download Options

This is the last official numbered release. While dated, it remains the standard for users who need a fixed, tested version. You can find it on the SquirrelMail SourceForge page .

Supports versions as old as 4.1.0, but requires specific patches for PHP 7.x and 8.x found in SVN snapshots.