In the past one of the first steps was to update the 'recommended versions' at dir auths so operators get to see an indicator on Relay Search and in their logs if they run old versions of tor, even if they do not have any usable ContactInfo that can be used to potentially reach them.
dir auths still recommend running tor 0.4.6.x versions today, so relay operators never got any indicator on RS or in their logs - this is a missed opportunity.
the current list of recommended server versions [1]:
server-versions 0.4.5.5-rc, 0.4.5.6, 0.4.5.7, 0.4.5.8, 0.4.5.9, 0.4.5.10, 0.4.5.11, 0.4.5.12, 0.4.5.14, 0.4.6.1-alpha, 0.4.6.2-alpha, 0.4.6.3-rc, 0.4.6.4-rc, 0.4.6.5, 0.4.6.6, 0.4.6.7, 0.4.6.8, 0.4.6.9, 0.4.6.10, 0.4.6.12, 0.4.7.1-alpha, 0.4.7.2-alpha, 0.4.7.3-alpha, 0.4.7.4-alpha, 0.4.7.5-alpha, 0.4.7.6-rc, 0.4.7.7, 0.4.7.8, 0.4.7.10
actively and regularly maintaining that list and making a more clear and prominent indicator on Relay Search would help the tor network.