o Major security fixes (directory authorities):

    - Directory authorities now include a digest of each relay's
      identity key as a part of its microdescriptor.

      This is a workaround for bug #11743, where Tor clients do not
      support receiving multiple microdescriptors with the same SHA256
      digest in the same consensus. When clients receive a consensus
      like this, they only use one of the relays. Without this fix, a
      hostile relay could selectively disable client use of target
      relays by constucting a router descriptor with a different
      identity and the same microdescriptor parameters and getting the
      authorities to list it in a microdescriptor consensus. This fix
      prevents an attacker from causing a microdescriptor collision,
      because the router's identity is not forgeable.