The current release version of Jetty is 9.4. Support is still provided for Jetty 9.2 and 9.3, and maintenance releases are provided for Jetty 7 and Jetty 8 when needed.
The most up-to-date distributions can be found on the Jetty Downloads page. It is worth noting that current releases of Jetty require Java 1.8 to be installed, which can be downloaded from Oracle.
The code base for Jetty is hosted on GitHub. Users are free to suggest enhancements, report bugs and even submit changes themselves. Information about contributing to Jetty can be found here.
Official Jetty documentation is hosted on the Eclipse Jetty site. In addition to current version documentation, the site provides documentation for prior versions of Jetty. JavaDocs and Source XRef documentation for Jetty can be found on the Jetty Downloads page.