lwt-zmq 1.0-beta4

Error log

The package failed to build. The error log from opam follows.

Opam plugin "depext" may require upgrading/reinstalling. Reinstall the plugin on the current switch? [Y/n] y
The following actions will be performed:
  - recompile opam-depext 1.2.3

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-> retrieved opam-depext.1.2.3  (cached)
-> removed   opam-depext.1.2.3
-> installed opam-depext.1.2.3
Done.

<><> opam-depext.1.2.3 installed successfully <><><><><><><><><><><><><><><><><>
=> opam-depext is unnecessary when used with opam >= 2.1. Please use opam install directly instead
# Run eval $(opam env) to update the current shell environment

<><> Carrying on to "opam depext -viy lwt-zmq.1.0-beta4 uint.1.2.1 stdlib-shims.0.3.0 seq.0.3.1 result.1.5 ounit2.2.2.7 ounit.2.2.7 ocplib-endian.1.2 ocamlfind.1.9.6 ocamlbuild.0.14.3 ocaml-zmq.0 ocaml-syntax-shims.1.0.0 mmap.1.2.0 lwt.5.5.0 dune-configurator.3.16.0 dune.3.16.0 csexp.1.5.2 cppo.1.7.0 bigarray-compat.1.1.0 base-unsafe-string.base base-bytes.base" 

Since version 2.1, opam now handles external dependencies alongside OCaml ones, and the `depext` plugin interface is provided for backwards compatibility only. Consider using your usual `opam install` command to install both OCaml and system dependencies, or `opam install <pkg> --depext-only` if you want to only install external dependencies.
# Detecting depexts using vars: arch=x86_64, os=linux, os-distribution=debian, os-family=debian
[ERROR] No solution for lwt-zmq.1.0-beta4 & uint.1.2.1 & stdlib-shims.0.3.0 & seq.0.3.1 & result.1.5 & ounit2.2.2.7 & ounit.2.2.7 & ocplib-endian.1.2 & ocamlfind.1.9.6 & ocamlbuild.0.14.3 & ocaml-zmq.0 & ocaml-syntax-shims.1.0.0 & mmap.1.2.0 & lwt.5.5.0 & dune-configurator.3.16.0 & dune.3.16.0 & csexp.1.5.2 & cppo.1.7.0 & bigarray-compat.1.1.0 & base-unsafe-string.base & base-bytes.base:   * Missing dependency:
            - lwt-zmq > 2.1.0
            no matching version


Command failed: opam --cli=2.1 list --readonly --external '--resolve=lwt-zmq.1.0-beta4,uint.1.2.1,stdlib-shims.0.3.0,seq.0.3.1,result.1.5,ounit2.2.2.7,ounit.2.2.7,ocplib-endian.1.2,ocamlfind.1.9.6,ocamlbuild.0.14.3,ocaml-zmq.0,ocaml-syntax-shims.1.0.0,mmap.1.2.0,lwt.5.5.0,dune-configurator.3.16.0,dune.3.16.0,csexp.1.5.2,cppo.1.7.0,bigarray-compat.1.1.0,base-unsafe-string.base,base-bytes.base' --color=never returned 20