According to the box, the extension should be compatible with 1.21+, but choosing 1.21 in the download box gives me an empty TAR. So I went with the 1.23 image which seems to work (my wiki is on 1.21.2) - at least I get no errors (yet),
Would however like to point out that the documentation lacks a proper description, or link to a description, of how to use magic words. I've personally never come across having to use them before and a link or code sample to something similar to Template:Disambiguation would be nice.