[tor-relays] is explicit DirPort needed anymore under Tor 0.2.8.6?

The release notes for Tor 0.2.8.6 have this tidbit about the DirPort:

"Previously only relays that explicitly opened a directory port (DirPort) accepted directory requests from clients. Now all relays, with and without a DirPort, accept and serve tunneled directory requests that they receive through their ORPort. You can disable this behavior using the new DirCache option. Closes ticket 12538."

With this new behavior, is there any reason to keep an open DirPort on our relays? If I just use an ORPort on 443 (or another reachable TCP port) is this sufficient? Might it make sense to leave the DirPort up for a while for legacy clients? Will (up-to-date) authorities have any concerns with a ORPort-only relay?

Thanks.