All notifications by postal services shall be by registered letter.[ 141 ]
Where notification is effected in accordance with paragraph 1, the letter shall be deemed to be delivered to the addressee on the tenth day following its handover to the postal service provider, unless it has failed to reach the addressee or has reached him at a later date; in the event of any dispute, it shall be incumbent on the European Patent Office to establish that the letter has reached its destination or to establish the date on which the letter was delivered to the addressee, as the case may be.
Notification in accordance with paragraph 1 shall be deemed to have been effected even if acceptance of the letter has been refused.
To the extent that notification by postal services is not covered by paragraphs 1 to 3, the law of the State in which the notification is made shall apply.