Hello,
It’s my pleasure to announce the version 2.1.0 of cmdliner
Cmdliner is an ISC-licensed library that allows the declarative and
compositional definition of command lines with excellent support for
command line interface user conventions and standards.
This releases consolidates additional work on command line completion. I added:
- Support for powershell auto-completion (details).
- Significant improvements to the
bashcompletion. - Updated
duneinstall instructions in the cookbook.
I’d like to thank @dbuenzli for his gracious feedback on these changes, and importantly for telling me “no” to several others beforehand 
For all the other details see the release notes.
Homepage: https://erratique.ch/software/cmdliner
Docs: https://erratique.ch/software/doc or odig doc cmdliner
Install: opam install cmdliner (once the PR is merged, may take a few days)