Package gen_server

Failed to find a solution:

no platform:
2024-01-29 15:12.45 [INFO] Solving for ocaml-base-compiler, ocaml,
                           gen_server using opam_repository_commit 251c5edf2ecdd2541c324dacb931c3606ee71eeb

2024-01-29 15:12.52 [INFO] base: eliminated all possibilities in 3.21 s

2024-01-29 15:12.52 [INFO] = base =

2024-01-29 15:12.52 [INFO] Can't find all required versions.
Selected: base.v0.16.3 base-bigarray.base base-domains.base base-nnp.base
          base-threads.base base-unix.base base_bigstring.v0.16.0
          base_quickcheck.v0.16.0 bin_prot.v0.16.0
          camlp4.4.02.0-1modular-implicits conf-which.1 core.v0.16.2
          csexp.1.5.2 dune.3.13.0 dune-configurator.3.13.0 fieldslib.v0.16.0
          int_repr.v0.16.0 jane-street-headers.v0.16.0 jst-config.v0.16.0
          num.1.5 ocaml-compiler-libs.v0.12.4 ocaml-config.3
          ocaml-options-vanilla.1 ocamlbuild.0.14.3 ocamlfind.1.9.6
          parsexp.v0.16.0 ppx_assert.v0.16.0 ppx_base.v0.16.0
          ppx_bench.v0.16.0 ppx_bin_prot.v0.16.0 ppx_cold.v0.16.0
          ppx_compare.v0.16.0 ppx_custom_printf.v0.16.0 ppx_derivers.1.2.1
          ppx_disable_unused_warnings.v0.16.0 ppx_enumerate.v0.16.0
          ppx_expect.v0.16.0 ppx_fields_conv.v0.16.0
          ppx_fixed_literal.v0.16.0 ppx_globalize.v0.16.0 ppx_hash.v0.16.0
          ppx_here.v0.16.0 ppx_ignore_instrumentation.v0.16.0
          ppx_inline_test.v0.16.1 ppx_jane.v0.16.0 ppx_let.v0.16.0
          ppx_log.v0.16.0 ppx_module_timer.v0.16.0 ppx_optcomp.v0.16.0
          ppx_optional.v0.16.0 ppx_pipebang.v0.16.0 ppx_sexp_conv.v0.16.0
          ppx_sexp_message.v0.16.0 ppx_sexp_value.v0.16.0 ppx_stable.v0.16.0
          ppx_stable_witness.v0.16.0 ppx_string.v0.16.0 ppx_tydi.v0.16.0
          ppx_typerep_conv.v0.16.0 ppx_variants_conv.v0.16.0 ppxlib.0.31.0
          re.1.11.0 seq.base sexplib.v0.16.0 sexplib0.v0.16.0
          splittable_random.v0.16.0 stdio.v0.16.0 stdlib-shims.0.3.0
          time_now.v0.16.0 typerep.v0.16.0 variantslib.v0.16.0
          gen_server&ocaml&ocaml-base-compiler ocaml-base-compiler
          ocaml-base-compiler ocaml base-domains ocaml ocaml-base-compiler
- async -> async.109.17.00
    gen_server 2.0.1 requires < v0.10
- async_core -> (problem)
    async 109.17.00 requires = 109.15.00
    Rejected candidates:
      async_core.109.55.02: Incompatible with restriction: = 109.15.00
      async_core.109.55.00: Incompatible with restriction: = 109.15.00
      async_core.109.53.00: Incompatible with restriction: = 109.15.00
      async_core.109.47.00: Incompatible with restriction: = 109.15.00
      async_core.109.45.00: Incompatible with restriction: = 109.15.00
      ...
- async_extra -> async_extra.109.17.00
    async 109.17.00 requires = 109.17.00
- async_unix -> async_unix.109.18.00
    async 109.17.00 requires >= 109.17.00 & <= 109.18.00
- gen_server -> gen_server.2.0.1
    User requested = 2.0.1
- herelib -> (problem)
    async_unix 109.18.00 requires = 109.15.00
    Rejected candidates:
      herelib.112.35.00: Incompatible with restriction: = 109.15.00
      herelib.109.35.02: Incompatible with restriction: = 109.15.00
      herelib.109.35.00: Incompatible with restriction: = 109.15.00
      herelib.109.15.00: Requires ocaml < 4.06.0
      herelib.109.14.00: Incompatible with restriction: = 109.15.00
      ...
- ocaml -> ocaml.5.1.0
    User requested <= 5.1.0
- ocaml-base-compiler -> ocaml-base-compiler.5.1.0
    User requested >= 4.04.1
    ocaml-base-compiler|ocaml-variants|ocaml-system|dkml-base-compiler ocaml-base-compiler requires >= 5.1.0~ & < 5.1.1~
- ocaml-variants -> (problem)
    Rejected candidates:
      ocaml-variants.5.3.0+trunk: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler
      ocaml-variants.5.2.0+trunk: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler
      ocaml-variants.5.1.2+trunk: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler
      ocaml-variants.5.1.1+tsan: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler
      ocaml-variants.5.1.1+options: In same conflict class (ocaml-core-compiler) as ocaml-base-compiler
      ...