Apple has released Darwin 7.0 to developers.

Darwin 7.0 is the underlying code at the core of Mac OS X 10.3 (Panther), which the company released on Friday.

All software built for Darwin should be able to run unmodified on Mac OS X. However Darwin does not include all Mac OS X's features, such as the Cocoa and Carbon toolkits – so many OS X applications will not run on Darwin, Apple said.

The distribution includes a large number of source projects. The released version of each Darwin project is available to browse or download as a source archive.

Apple expects Darwin to become the foundation for a complete, stand-alone open-source operating system distribution.