  o Minor features (required protocols):
    - Directory authorities now vote to require relays to support certain
      protocols, all of which have been implemented since 0.4.7.4-alpha or
      earlier.
      These include improved support for connecting to relays on IPv6,
      NtorV3, running as a rate-limited introduction point,
      authenticated SENDMEs, and congestion control.
      Part of ticket 40836.
    - Directory authorities now vote to require clients to support the
      authenticated SENDME feature, which was introduced in 0.4.1.1-alpha.
      Part of ticket 40836.

  o Minor features (recommended protocols):
    - Directory authorities now vote to recommend that clients
      support certain protocols beyond those that are required.
      These include improved support for connecting to relays on IPv6,
      NtorV3, and congestion control.
      Part of ticket 40836.
