Although the Yubikeys above support PIV credentials, encrypting and decrypting with a PIV credential requires the use of a different command for the encryption and decryption.
Currently the notes application at the initial release v1.0 only supports GnuPG encryption. I hope to include PIV based encryption keys in a future release by making the encryption and decryption code auto detect from the 'config' file.
Please let me know if you will find this useful.