Build Log: cohttp-async.6.2.0

Can't find all required versions. Selected: base-bigarray.base base-domains.base base-effects.base base-nnp.base base-threads.base base-unix.base ocaml-base-compiler.5.4.0 ocaml-config.3 ocaml-options-vanilla.1 ocaml&cohttp-async ocaml-base-compiler ocaml-base-compiler system-mingw system-mingw|system-msvc&winpthreads ocaml base-domains ocaml-variants ocaml-base-compiler - cohttp-async -> (problem) User requested = 6.2.0 Rejected candidates: cohttp-async.6.2.0: Requires ocaml >= 4.14 & < 5.3.0 - ocaml -> ocaml.5.4.0 User requested = 5.4.0 - ocaml-compiler -> ocaml-compiler.5.4.0 ocaml-base-compiler 5.4.0 requires = 5.4.0 - ocaml-variants -> (problem) Rejected candidates: ocaml-variants.5.5.0+trunk: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler ocaml-variants.5.4.1+trunk: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler ocaml-variants.5.4.0+options: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler ocaml-variants.5.4.0~rc1+options: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler ocaml-variants.5.4.0~beta2+options: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler ... - system-mingw -> (problem) No known implementations at all