Regarding database availability:

In addition to MySQL and PostgreSQL, upstream Roundcubemail includes support
for SQLite.  This has been disabled in the Fedora version (for the time being)
because Roundcube requires the SQLite2-compatible mainline PHP SQLite extension.
This extension is unavailable in Fedora in favor of the SQLite3-compatible PDO
SQLite extension (php-pdo package).  For this reason, we have disabled SQLite
support in Roundcube.  If upstream releases a new version that supports the 
PDO extension, or if SQLite2 support for PHP becomes available in Fedora, we
will re-enable SQLite support in Roundcubemail.

Jon Ciesla
05/11/2007