The opam repository archival process has set the minimum supported OCaml version to 4.08 for opam repository. It logically follows that opam-repo-ci should only test against OCaml >= 4.08.
The purpose of this post is to get a sense of whether the rest of the OCaml infrastructure should also adopt the same lower bound. The current lower bound is 4.02.
Specific examples include OCaml-CI. Individual projects can already opt out of testing on older platforms by adding a lower bound in the opam file.
Docker base images are built for all versions of OCaml used in the CI systems. These images are published weekly on Docker Hub. We know that these images are also used by the community, but the pull counter is not broken down by individual tag. Potentially only the latest OCaml versions are being used.
Users impacted by packages which have been archived from opam repository can easily restore the packages by adding the archive repository to the opam switch. This only needs to be done once. Users can build their own Docker base images, but they would need to be rebuilt periodically to keep them up to date.
Would removing testing on < 4.08 in OCaml CI or removing the Docker base images < 4.08 impact you?