>From the upstream homepage listed above: "SpiderMonkey 31 <https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey/Releases/31> is the most recent standalone source code release. It is largely the same engine that shipped with Firefox 31. Full source code is available here: https://people.mozilla.org/~sstangl/mozjs-31.2.0.rc0.tar.bz2
The next release will be SpiderMonkey 38, around May 2015." Regards, Gerardo