The router protocol versions section in dir-spec is out of date
I doubt clients do this: they only download the consensus, not votes:
A client should believe that a router supports a given feature if that
feature is supported by the router or protocol versions in more than half
of the live networkstatuses' "v" entries for that router.
https://gitweb.torproject.org/torspec.git/tree/dir-spec.txt#n3493