It's always, always, always time for MMP to do that, and they even have a web page for it, don't they?
http://www.multimanpublishing.com/News/tabid/82/Default.aspx
For the most part, they don't bother to update their own production schedule, as you can see for yourself -- last entry May 2019 -- what a joke.
This is an ongoing problem, but fans of MMP look the other way and hate that I keep bringing this up. One issue might be the puppet masters at Hasbro, because it would take about 5 minutes per week to keep that web page updated. But that can't be the whole story, because MMP publishes more than ASL; games and products not owned by Hasbro.
So, one must conclude they just aren't interested in keeping their customers informed regularly. Which is why GMT (and most everybody else) kicks their behinds in that department every single month.
For this lack of communication, I don't buy any of MMPs non-ASL products. They don't deserve my business on those other product lines.
MMP provides updates on Fakebook from time-to-time. You might check that out.