User blog comment:B214/Question and Answers 3/@comment-79.130.78.230-20140719120320/@comment-24502975-20140719171649

Oh, so DX1 really isn't part of the main volumes? That explains why there's about double the short stories in it than the past volumes. Alright, that makes sense, so it'll be released a little less than a month after volume 20 (assuming a new volume is every 4 months as it has been). Thanks for clarifying.