After roughly two years of development, the first stable release of Roundcube was announced on March 4, 2008.
cPanel adopted Roundcube as its bundled webmail client, replacing SquirrelMail. On May 3, 2015, Roundcube announced, in partnership with
Kolab Systems AG, a plan to completely rewrite the application as Roundcube Next. A
crowdfunding campaign was set up to finance the project. The $80,000 goal was reached on June 24, 2015, and the final amount raised was US$103,541. Roundcube Next was intended to add calendar, chat, and file management features using
WebRTC, with connectors for services such as
Dropbox and
ownCloud. Kolab Systems and Roundcube halted development in 2016, and backers received no updates or refunds. A Roundcube developer later stated that the project had no ownership over the Roundcube Next campaign. In November 2023,
Nextcloud announced a partnership with Roundcube. == Architecture ==