FIDO2/ed25519-sk key reported as invalid

[ofekd]

I am using an ed25519-sk key as per the Yubikey docs:

https://developers.yubico.com/SSH/

It works fine running the ssh command. Relevant logs suggest the SSH used may be too old:

D, [2024-10-18T04:49:05.793655 #998330] DEBUG -- net.ssh.transport.server_version[7f8]: local is `SSH-2.0-Ruby/Net::SSH_7.3.0 x86_64-linux'
D, [2024-10-18T04:49:05.882180 #998330] DEBUG -- net.ssh.transport.server_version[7f8]: remote is `SSH-2.0-OpenSSH_9.6p1 Ubuntu-3ubuntu13.5'
....
E, [2024-10-18T04:49:06.449335 #998330] ERROR -- net.ssh.authentication.key_manager[85c]: could not load public key file `/<redacted>/.ssh/id_ed25519_sk.pub': Net::SSH::Exception (public key at /<redacted>/.ssh/id_ed25519_sk.pub is not valid)

I wonder if it could be updated, if I could update it myself locally, or maybe use the ssh version installed on my computed.

I do not use ssh-agent.

As a workaround, I've reverted to a regular key