The project was started in 2005 with an alpha version. Meanwhile Roundcube has reached the version currently available a mature state.
Roundcube has a wide range of functions, such as a spelling checker, multi-language, send e -mail attachments, full support for MIME and HTML message formats and an LDAP address book. In addition, the functionality of Roundcube can be extended with plug-ins. It can thus be integrated, inter alia, a calendar and organizer. Numerous plug-ins can be found in the " plug- in repository ".
To install a database is required (eg MySQL) next to PHP. While Roundcube to version 0.1.1 based on PHP4 is supported since version 0.2 only PHP5.