The Arena format will no longer be the only available tournament format on Lichess. The site is about to introduce Swiss format tournaments, the result of a long debate in the site’s forums. Round robin tournaments might be the next feature. There is a Charity Blitz Tournament to be held on lichess.org (with Kramnik, Nepomniachtchi, Grischuk and others) which will be played as a round robin. Since this shows that round robins are already implemented there is a debate to make them accessible in general. These developments have been caused by the recent run on the site by many smaller clubs whose members wanted an alternative to the Arena format.