o Major features (Ed25519 keys, keypinning)
    - The key-pinning option on directory authorities is now
      advisory-only by default. In a future version, or when the
      AuthDirPinKeys option is set, pins are enforced again.
      Disabling key-pinning seemed like a good idea so that we can
      survive the fallout of any usability problems associated with
      ed25519 keys. Closes ticket 17135.