since you direct everyone to your github, the idea that at the top of your README.md, you have a list of requirements for the latest version is not unreasonable.
if you ever start making use of releases and tags (i only see 1 tag and 0 releases), which i recommend, you can add the requirements for each release there.
i am sure that within the 71 commits you have on your repo, there is a version compatible with 7.4 and zc1.5.7d (maybe not); but had you made use of releases and tags, it would allow users the opportunity to use a version that fits their specific needs.
browbeating a user is so beneath you; unless you decide to start offering a hosting package. in which case, on this forum, it is expected.
best.
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