After a couple of years of alpha and beta version releases, the first official stable version of ROS-2 was released in December 2017. The distro was named Ardent Apalone, a typical alphabetical order naming style OSRF usually follows to name their ROS distributions. The second release was in June 2018, called Bouncy Bolson. This version came with added features and bug fixes and support for Ubuntu 18.04 and Windows 10 with Visual Studio 2017. The third version was called Crystal Clemmys and was released in December 2018. All of the ROS distributions are code-named. For instance, this release is code-named crystal, while the former two are named bouncy and ardent, respectively.

At the time of writing this book, the latest version is Dashing Diademata, which was released on May 31, 2019 and code-named dashing.

Ardent and bouncy have already reached their End Of License (EOL) deadlines and hence aren't supported. The third stable release, crystal, has an EOL deadline of December 2019 and the only long-term stable release is dashing, which has an EOL deadline of May 2021.