It's DTLS-OK according to IANA.
I tested ED25519 certificates on TLS 1.2 and it worked fine.
openssl s_server -port 4321 -cert server-cert.pem -key server-key.pem -CAfile client-cert.pem -tls1_2 -sigalgs ed25519
openssl s_client -bind localhost:1234 -connect localhost:4321 -cert client-cert.pem -key client-key.pem -CAfile server-cert.pem -tls1_2 -sigalgs ed25519
openssl s_client -bind localhost:1234 -connect localhost:4321 -cert client-cert.pem -key client-key.pem -CAfile server-cert.pem -tls1_2 -sigalgs ed25519
But I get a "no shared cipher" error
(on the server)
if I just replace -tls1_2 with -dtls1_2 on those two commands.
The certs and keys are self-signed for both the server and client and where generated by this command.
openssl req -x509 -newkey ed25519 -subj "/CN=localhost" -nodes -addext keyUsage=digitalSignature -keyout key.pem -out cert.pem
