Elementary OS

elementary OS is an Ubuntu based distribution using the Pantheon desktop interface. Some of its more interesting features include a unique GTK+ and icon theme for GNOME, the Midori web browser, and several applications developed in-house (e.g. Dexter, an address book and Postler, an email client).

elementary OS uses the home-built Pantheon desktop environment and the Gala window manager.

History
The Elementary project began in June of 2009 with the release of an icon set for Ubuntu. The first release, Jupiter, was made available on March 31, 2011. It featured a customized Gnome desktop, and was based on Ubuntu 10.10.

The second release, 0.2 Luna, was released in August of 2013. It was based on Ubunut 12.04 LTS, and featured the project's new Pantheon desktop environment.

The third release, 0.3 Freya, was released in December 9, 2015. It was based on Ubunut 14.04 LTS.

The fourth release, 0.4 Loki, was released in May 7, 2017. It was based on Ubunut 16.04 LTS.

The fifth and current latest release, 5.0 Juno, was released in October 16, 2018. It is based on Ubunut 18.04 LTS.

Release Schedule
elementary OS does not have a strict release cadence, instead following a "release when ready" model. However, releases generally occur about a year after the release of the Ubuntu LTS release.