Package camlp4

Failed to find a solution:

no platform:
2026-02-04 14:33.29 [INFO] Solving for ocaml-base-compiler,
                           camlp4, constraints ocaml-base-compiler<=5.4.0,
                           camlp4=4.02.0-1modular-implicits using opam_repository_commit 45c04602c2fc908af6d1b17ba39c7517d58cb274

2026-02-04 14:33.30 [INFO] base: eliminated all possibilities in 0.25 s

2026-02-04 14:33.30 [INFO] = base =

2026-02-04 14:33.30 [INFO] Can't find all required versions.
Selected: conf-which.1 ocaml.5.6.0 ocamlbuild.0.16.1 ocamlfind.1.9.8
          camlp4&ocaml-base-compiler ocaml-base-compiler
- camlp4 -> camlp4.4.02.0-1modular-implicits
    User requested = 4.02.0-1modular-implicits
- ocaml-base-compiler -> (problem)
    User requested <= 5.4.0
    ocaml-base-compiler|ocaml-variants|ocaml-system|dkml-base-compiler ocaml-base-compiler requires = 5.6.0
    Rejected candidates:
      ocaml-base-compiler.5.4.0: Incompatible with restriction: = 5.6.0
      ocaml-base-compiler.5.4.0~rc1: Incompatible with restriction: = 5.6.0
      ocaml-base-compiler.5.4.0~beta2: Incompatible with restriction: = 5.6.0
      ocaml-base-compiler.5.4.0~beta1: Incompatible with restriction: = 5.6.0
      ocaml-base-compiler.5.4.0~alpha1: Incompatible with restriction: = 5.6.0
      ...
- ocaml-variants -> (problem)
    camlp4 4.02.0-1modular-implicits requires = 4.02.0+modular-implicits | = 4.02.1+modular-implicits-ber
    Rejected candidates:
      ocaml-variants.5.6.0+trunk: Incompatible with restriction: = 4.02.0+modular-implicits | = 4.02.1+modular-implicits-ber
      ocaml-variants.5.5.0+trunk: Incompatible with restriction: = 4.02.0+modular-implicits | = 4.02.1+modular-implicits-ber
      ocaml-variants.5.4.1+trunk: Incompatible with restriction: = 4.02.0+modular-implicits | = 4.02.1+modular-implicits-ber
      ocaml-variants.5.4.0+options: Incompatible with restriction: = 4.02.0+modular-implicits | = 4.02.1+modular-implicits-ber
      ocaml-variants.5.4.0~rc1+options: Incompatible with restriction: = 4.02.0+modular-implicits | = 4.02.1+modular-implicits-ber
      ...