Roundcube Webmail is a browser-based multilingual IMAP client with an
application-like user interface.  It provides full functionality you
expect from an email client, including MIME support, address book, folder
management, message searching and spell checking.  Roundcube Webmail is
written in PHP and requires the MySQL, PostgreSQL or SQLite database.
With its plugin API it is easily extendable and the user interface is
fully customizable using skins.

The code designed to run on a webserver is mainly written in PHP and
Javascript.  It includes a custom framework with an IMAP library derived
from IlohaMail and requires a set of external libraries (see composer.json
and jsdeps.json files).

The most noteworthy changes of Roundcube 1.6:

* PHP 8.1 support
* Dropped support for PHP < 7.3
* Support responses (snippets) in HTML format
* Option to purge deleted mails older than 30, 60 or 90 days
* Unified and simplified services connection config options
* Removed the Classic and Larry skins from the release packages
* SQLite: Use foreign keys, require SQLite >= 3.6.19