Hi, when I pointed you at Flow back in Library to parse JavaScript in opam? , I’m pretty sure I tried it on OCaml 4.09. I did pin to the latest commit in the repo directly though, not the version published on opam, which was quite old: Library to parse JavaScript in opam?
But looking at the published opam package, even there is says that the required OCaml version is >=4.03.0, so it should still work on say 4.09.
EDIT: confirmed working with 4.09