Yes, but technically you always could.
Because you fetch an invoice, that invoice contains the message. And now you can prove that you wrote the message, and that the recipient received the message: the invoice they sign has your message in it, and your key (often a made up one for that payment).
Rusty Russell
npub179…elz4s
2024-09-26 23:45:25
in reply to nevent1q…xkeg
Author Public Key
npub179e9tp4yqtqx4myp35283fz64gxuzmr6n3yxnktux5pnd5t03eps0elz4sPublished at
2024-09-26 23:45:25Event JSON
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