Patches [1] are being prepared to remove Tor relays running end-of-life versions of Tor eventually.
Affected relays as of 2019-09-03 16:00 UTC
#relays 1276 CW Fraction 13.25 % Guard 16.91 % Exit 2.19 %
Want to know if your relay is affected? Here is a list of affected relays (updated daily): https://nusenu.github.io/OrNetStats/eolrelays
The Tor Relay Guide has instructions to help you stay on maintained Tor releases. https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkTeam/CoreTorR...
[1] https://trac.torproject.org/projects/tor/ticket/31549
Tor people are sending out emails (cc'ing network-health): https://lists.torproject.org/cgi-bin/mailman/listinfo/network-health