Here are the 1.7 release notes. They didn't get a lot of review when originally merged. If there's anything missing here you want to see, please speak up, or better yet submit at PR and tag it beta-nominated.
Our only new language feature is a breaking change?
I found two typos. Also, the "Stabilised APIs" list really hard to read. I'll send you a PR to fix the typos and make it a nested list real quick
Custom hasher support in HashMap was stabilized in 1.7, but it does not appear in the release notes.
Thanks @bytwise! I'll add it.