The Rust toolset has two major components: the compiler (rustc) and a combined build tool or dependency manager (Cargo). This toolset comes in three frequently released versions:
- Nightly: This is the daily successful build of the master development branch. This contains all the features, some of which are unstable.
- Beta: This is released every six weeks; a new beta branch is taken from nightly. It contains only features that are flagged as stable.
- Stable: This is released every six weeks; the previous beta branch becomes the new stable.
Developers are encouraged to mainly use stable. However, the nightly version enables many useful features, which is why some libraries and programs require it.