Either is probably ok, but the better choice is probably "issue." An "edition" usually refers to a different version of the same basic content. For example, if you publish a textbook in the year 2018, and then two years later, you publish the same textbook but with a few minor errors fixed, it might be the "second edition." With newspapers, sometimes they use the word "edition" to describe a special version of the newspaper: the Sunday edition of some newspaper may be bigger than the normal newspaper that comes out on Monday-Friday. Or it may have special content-- a section about new movies that only comes out on Sunday. "Issues" of a newspaper, magazine, etc., usually refers to the separate publications released on a schedule. Issues of a newspaper, issues of a magazine, the February issue, the March 15 issue of a newspaper. "Volumes" can also be used, but it usually is reserved for something that is only going to be published for a certain set number, or maybe published all at once. For example, a big encyclopedia may be published in 10 volumes: A-C, D-F, G-H, J-K, L-M, N-O, P-Q, R-S, T-U, and V-Z. Sometimes these words overlap. Sometimes a magazine company or newspaper company likes to refer to it's "issues" as "editions" or "volumes." But what I wrote above is the most common use.