Aquamacs is a heavily customized emacs based on GNU Emacs. I'm not sure how or if Aquamacs resynchronizes with GNU Emacs, but in principle, a new release of Aquamacs might start with this release of GNU Emacs as a base.

In general, I've found the platform integrations of Aquamacs to not be worth the trouble and package incompatibilities that they appear to introduce. I'm not using OS X these days, but up until a couple of months ago, I tended to use either the "Emacs for OSX" distribution, or compile my own via Homebrew.

I think it's pretty common for people to recommend using one of the more "vanilla" versions of GNU Emacs over Aquamacs these days.