ECMAScript 5 support
ECMAScript 5 support was added to Rhino by Raphael Speyer during a Google Summer of Code project mentored by Norris Boyd. Rhino 1.7R3 supports most of ES5 except for Strict Mode.
New AST API
CommonJS module support
A fully compliant CommonJS module implementation was contributed by Attila Szegedi. CommonJS modules are also available in the Rhino shell using the -modules, -main, and -sandbox command line options.
JS Objects implement Java collections
JSDoc comment parsing
The Rhino parser is now capable of recognizing JSDoc-like comments (starting with /**). This feature is disabled by default and has to be enabled by setting the corresponding flag in the CompilerEnviron object.
Rhino has seen some performance improvements since the last release which are most notable when running benchmarks or the test suite.