This removal took effect around 2020-05-20 as you can see on the tor metrics graphs:
https://metrics.torproject.org/versions.html?start=2020-05-01&end=2020-0... (where the line for 0.2.9 and 0.4.0 stops)
Unfortunately over 350 relays (105 guards, 5.7% guard probability) where not upgraded to a supported version and got removed.
It is recommended to configure your relays to auto-update to minimize the risk of outdated software. https://community.torproject.org/relay/setup/guard/
nusenu:
Tor developers are preparing the removal of outdated Tor relays from the network https://trac.torproject.org/projects/tor/ticket/32672
If you are one of the affected operators (listed bellow), please upgrade to a supported tor release to protect yourself and the entire network from attacks exploiting older tor versions.
https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkTeam/CoreTorR...
The first 8 entries in the table bellow are in BCC of this email.