The news that MathJax CDN shutting down on April 30, 2017 was recently brought to my attention. I have updated ChatJax to use the alternate server given in the MathJax post. It seems to work well, but if StackExchange is going to host a local copy to use with the sites that support MathJax, I will update ChatJax to use that server instead.
Have any SE developers seen this news, and if so, what are the SE plans for continued support of MathJax?