Mopidy follows Semantic Versioning. In summary this means that our version numbers have three parts, MAJOR.MINOR.PATCH, which change according to the following rules:
When we make incompatible API changes, we increase the MAJOR number.
When we add features in a backwards-compatible manner, we increase the MINOR number.
When we fix bugs in a backwards-compatible manner, we increase the PATCH number.
The promise is that if you make a Mopidy extension for Mopidy 1.0, it should work unchanged with any Mopidy 1.x release, but probably not with 2.0. When a new major version is released, you must review the incompatible changes and update your extension accordingly.
We intend to have about one feature release every month in periods of active development. The features added is a mix of what we feel is most important/requested of the missing features, and features we develop just because we find them fun to make, even though they may be useful for very few users or for a limited use case.
Bugfix releases will be released whenever we discover bugs that are too serious to wait for the next feature release. We will only release bugfix releases for the last feature release. E.g. when 1.2.0 is released, we will no longer provide bugfix releases for the 1.1.x series. In other words, there will be just a single supported release at any point in time. This is to not spread our limited resources too thin.