Hmm, 1.12.4 may be difficult:

Setup: At least the following dependencies are missing:
aeson ==0.7.*,
highlighting-kate >=0.5.7 && <0.6,
pandoc-types >=1.12.3.3 && <1.13,
tagsoup >=0.13.1 && <0.14,
texmath >=0.6.6.1 && <0.7,
yaml >=0.8.8.2 && <0.9

It looks like https://github.com/jgm/pandoc/commit/c8f97d3d418f929a1f499a9ef37c17d71f282d45 is the bugfix I need for pypandoc that's in 1.12.4, so perhaps just backporting that will work.

Looks like too many other changes before that patch to backport cleanly.

Thanks for the request: I am thinking to do a major rebase of EPEL Haskell packages next year.

Do you need this to build pypandoc in EPEL7?

Yes, that's what prompted it.

Would 1.12.3.3 still be helpful?

At this point, I don't think it's needed.