If I wrote something about the new equation editor in ATTO it was because DMR is dependant on DragMath that will not be part of core Moodle starting from Moodle 2.8.
But unfortunately the new equation editor is just an ATTO plugin and I don't think it can be used outside from ATTO.
So that would not work for DMR which is just a shortanswer question with an applet for the teacher or student to enter his response.
The only solution I see is to do a new version of DMR for Moodle 2.7 and to include DragMath in it, so that it doesn't stop from working when Moodle 2.8 will be released.
I will do it but I can't give any date for the release. Probably before the end of July.
The easy part is to upgrade all the php code. This is easy because mostly you just copy and paste code from 2.7 version of the shortanswer question type just changing "shortanswer" to "dmr" (well there are some more things to look at, but you get the idea)