Both the documentation and the CLI help text suggest that this is a valid command, but the command itself rejects it.
$ docker --version=false
Usage: docker [OPTIONS] COMMAND [arg...]
A self-sufficient runtime for linux containers.
Options:
[...]
-v, --version=false Print version information and quit
Commands:
attach Attach to a running container
[...]
Both the documentation and the CLI help text suggest that this is a valid command, but the command itself rejects it.