IEC 62351 - Power Systems Communication Security 3:8.8: Part 3, 8.8: TLSv1.3 extensions (supported versions, cookie, signature algorithms, supported groups, key share, server name indication, certificate authorities, PSK key agreement, early data)

What does 3:8.8 require?

Conforming TLSv1.3 implementations support the extensions the profile selects: supported versions, cookie, signature algorithms, supported groups, key share, server name indication, certificate authorities and PSK-based key agreement, and do not use early data (0-RTT).