(3)All notices and all written communications addressed to a patentee, or to any applicant or opponent in any proceedings under the Act or these rules, and all documents forwarded to the patentee or to the said applicant or opponent, shall, except when they are sent by special messenger, be sent by registered post or speed post [* * *] [Omitted 'or courier service' by Notification No. G.S.R. 523(E), dated 16.5.2016 (w.e.f. 2.5.2003).] or by electronic transmission duly authenticated.
