(6)Notwithstanding anything contained in the foregoing sub-rules, the Tribunal shall, in cases of service of notice or order under sub-rule (4) and may in other cases also, if it is thought fit, order that the notice or order shall be served by sending a copy thereof, duly signed and sealed, by registered post with acknowledgement due to the person on whom such notice or order is to be served; the posting of the notice or order shall be sufficient proof of the service of such notice or order on the person concerned.
