Capturing a client's negotiated SSL_version will enable server-side admins to understand with their application stakeholders are ready for server-side configuration changes requiring higher minimum TLS versions.
This can be done through a couple of different ways. First, we should record version counters in serverStatus. This will give a quick overview of the TLS ecosystem a server operates in, for humans and for machines. Secondly, the version should be logged, during connection establishment, so a manual inspection will reveal which versions were negotiated by particular IPs.
This would preferably be back-ported to 3.2, 3.4, and 3.6