Service of communication addresses specified for tax notices, with prioritized physical and electronic address rules and security standards. Service of notice and other communications under the Income tax Act is governed by newly inserted rule 127, prescribing a prioritized list of addresses for physical delivery (PAN database, address in the relevant return, last furnished return, company registered office) and for electronic delivery (email in the relevant return, email in the last return, company email on MCA website, or any email furnished by the addressee). The designated systems authority must specify procedures, formats and standards for secure electronic transmission and implement security, archival and retrieval policies.