Package ocaml-option-default-unsafe-string

Failed to find a solution:

no platform:
2024-01-29 15:12.15 [INFO] Solving for ocaml-base-compiler, ocaml,
                           ocaml-option-default-unsafe-string using opam_repository_commit 251c5edf2ecdd2541c324dacb931c3606ee71eeb

2024-01-29 15:12.20 [INFO] base: eliminated all possibilities in 2.47 s

2024-01-29 15:12.20 [INFO] = base =

2024-01-29 15:12.20 [INFO] Can't find all required versions.
Selected: base-bigarray.base base-threads.base base-unix.base ocaml-config.3
          ocaml-option-default-unsafe-string&ocaml&ocaml-base-compiler
          ocaml-base-compiler ocaml-base-compiler
- ocaml -> ocaml.4.14.2
    User requested <= 5.1.0
    ocaml-variants 4.14.2+trunk requires = 4.14.2
- ocaml-base-compiler -> (problem)
    User requested >= 4.04.1
    Rejected candidates:
      ocaml-base-compiler.5.1.1: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ocaml-base-compiler.5.1.1~rc1: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ocaml-base-compiler.5.1.0: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ocaml-base-compiler.5.1.0~rc3: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ocaml-base-compiler.5.1.0~rc2: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ...
- ocaml-option-default-unsafe-string -> ocaml-option-default-unsafe-string.1
    User requested = 1
- ocaml-variants -> ocaml-variants.4.14.2+trunk
    ocaml-option-default-unsafe-string 1 requires >= 4.12.0~ & < 5.0.0~~