The assessment order was served on assessee through designated e-mail ID of the AO. The draft assessment order was signed and the final order was not signed. Additions made in the draft assessment order and final assessment order is the same.  The assessee challenged the assessment order on the ground that unsigned assessment order was served on assessee hence the order is  in valid. On appeal the   Tribunal  held that signing of an assessment order by the AO is a mandatory requirement and not merely a procedural formality. Since the assessment order communicated to the assessee originated from the designated e-mail ID of the AO therefore, in terms of rule 127A the said document shall be deemed to be authenticated. The unsigned  assessment order served on the assessee is held to be invalid and quashed. Referred, Kilasho Devi Burman (Smt) v. CIT  (1986) 219 ITR 214 / 85 Taxman 346 (SC), Vijay Corporation v. ITO (2012) 18 taxmann.com 88/ 50 SOT 33(URO) (Mum)(Trib), Yeshoda Electricals v. ACIT (ITA No. 1175 / 2016 dt 3-2 -2021 (Bang)(Trib)      (AY. 2015 -16)