Changes between Spidermonkey 59 and 76 (current)

Hi,

The software that I'm developing currently has a very old version of Spidermonkey embedded (version 1.8.5). A year or so ago, we started trying to update it to version 59, though this work wasn't completed. We are now trying to update Spidermonkey to the most recent version (currently version 76).

I was just wondering, since version 59, have there been any major changes in the way that the engine works/requirements for building and embedding - e.g. is rust now required? Furthermore, is there a site listing the release notes for each version?

Many thanks,
Harry