The notifications provided for by this section and by Article L. 623-18 shall be made by registered letter with acknowledgement of receipt.
Sending by registered letter with acknowledgement of receipt may be replaced by delivering the letter to the addressee against a receipt, at the headquarters of the national plant variety authority, or by a message in electronic form in accordance with the procedures laid down by the head of the national authority to guarantee in particular the security of the dispatch.
If the address of the addressee is unknown, notification shall be made by publication of a notice in the Official Bulletin of the national plant variety authority.