PQC → classical fallback

Keep a PQC-only client working against legacy servers that have no PQC.

client offers PQC only → TLS Lane → classical-only server (OpenSSL < 3.5)

When you need it: A forward-leaning, PQC-only client that must still reach a legacy origin with no post-quantum support. Without help, that handshake just times out.
How it works: TLS Lane appends a classical group (X25519) at the tail of the upstream-bound ClientHello, so a classical-only server can still negotiate a shared secret.
Good to know: A connectivity adapter, not a security upgrade — the server leg is classical. It keeps a PQC-only client from breaking against old infrastructure.
TLS version: TLS 1.3

Enable sudo tlslane splice — on by default when splicing