o Minor features (fallback directories):
    - Select 200 fallback directories for each release.
      Closes ticket 20881.
    - Provide bandwidth and consensus weight for each candidate fallback in
      updateFallbackDirs.py.
      Closes ticket 20878.
    - Require fallback directories to have the same address and port for
      7 dayss. (Due to the number of relays with enough stability.) Relays
      whose OnionOO stability timer is reset on restart by bug 18050 should
      upgrade to Tor 0.2.8.7 or later, which has a fix for this issue.
      Closes ticket 20880; maintains short-term fix in e220214 in
      tor-0.2.8.2-alpha.
    - Make it easier to change the output sort order of fallbacks.
      Closes ticket 20822.
    - Exclude relays affected by 20499 from the fallback list. Exclude known
      affected versions, and any relay that delivers a stale consensus, as
      long as that consensus expired more than 24 hours ago.
      Closes ticket 20539.
    - Require fallbacks to have flags for 90% of the time (weighted decaying
      average), rather than 95%. This allows at least 73% of clients to
      bootstrap in the first 5 seconds without contacting an authority.
      Part of ticket 18828.
    - Display the fingerprint when downloading consensuses from fallbacks.
      Closes ticket 20908.
    - Allow 3 fallbacks per operator. (This is safe now we are choosing 200
      fallbacks.) Closes ticket 20912.
    - Reduce the minimum fallback bandwidth to 1 MByte/s.
      Part of #18828.
  o Minor bugfixes (fallback directories):
    - Stop failing when OUTPUT_COMMENTS is True in updateFallbackDirs.py.
      Closes ticket 20877; bugfix on commit 9998343 in tor-0.2.8.3-alpha.
    - Avoid checking fallback candidates' DirPorts if they are down in
      OnionOO. When a relay operator has multiple relays, this prioritises
      relays that are up over relays that are down.
      Closes ticket #20926; bugfix on 0.2.8.3-alpha.