---
upgrade:
  - |
    The `extract_swift_flags` tool no longer supports the `docbook` command.
    This previously allowed outputting of Docbook-formatted text but the
    feature was broken and unsupported by the community. reStructuredText
    should be used for everything.
  - |
    The `extract_swift_flags` tool no longer supports the `--from` argument.
    All Swift documentation has been converted to reStructuredText meaning
    there is no reason to keep this around.