Particularly he talks about issues the Chrome team had with deploying
TLS 1.3. One of the issues affects OpenSSL prereleases.
Some early versions of OpenSSL 1.1.1 (-pre6 and earlier) would allow
connections from TLS 1.3 clients, but they would try to do a connection
with a Draft TLS 1.3 version with a client that uses the final TLS 1.3
version. This obviously fails.
Long story short: If you happen to use such an OpenSSL pre version
you'll likely have connection issues as more and more software will
support TLS 1.3. So please update as soon as possible.