Section 122(4) in Rules Under the Land and Revenue Regulation
(4)In such tracts as may from time to time be notified by the State Government, service of the copy or copies, of the notice referred to above may be effected by despatch by registered post.Note. The State Government have notified that in the plains district of Assam the copies of the notice referred to in this rule may, where it is convenient, be served, by despatch by registered post.