UPDATE: Mathjax 2.3 is now live
We have deployed the latest Mathjax 2.3 beta on Math.SE. As with any beta release please post an answer to this question if you find any issues. We will be monitoring this thread closely along with the authors of Mathjax to ensure this release goes smoothly.
For a list of features included in this release check here
\selectfont-like functionality)? [Also, it's always fun to see you 'round here! :-)] $\endgroup$