concat `1.0.0` will  generate warnings if `concat::setup` is not included.  `1.1+` will generate a warning if it is included.  When I made this PR (part of a batch of PRs to all PL modules using concat) it wasn't yet clear what the version string the next concat release would use.  Now that we know it will be `1.1.0` would you prefer that I update it to `>= 1.1.0`?