Enable X25519MLKEM768 on Caddy

Caddy uses Go's TLS stack. From Caddy 2.10 (Go 1.24 and later), X25519MLKEM768 is offered and preferred by default.

Before you start

• Caddy 2.10 or later: caddy version.

Option 1: keep the defaults (simplest)

1. Look for a curves setting in your Caddyfile or JSON config: grep -n curves /etc/caddy/Caddyfile.
2. If there is none, upgrade to 2.10 or later and reload: caddy reload --config /etc/caddy/Caddyfile. Nothing else to change.

Option 2: list the curves yourself

1. In the site's tls block, put x25519mlkem768 first:

example.com {
	tls {
		curves x25519mlkem768 x25519
	}
}

2. Reload: caddy reload --config /etc/caddy/Caddyfile.

Then scan your domain below.