Service of notice for discontinued business permits notice to former partners or a company's principal officer for assessment. Section 284 empowers the Assessing Officer to serve notices for assessments under section 176 where a business is discontinued, permitting service on the person whose income is to be assessed, on any former member of a discontinued firm or association, or on a company's principal officer; the notice may include matters equivalent to those in a section 139(2) notice and the Income-tax Act applies to such notice as if it were issued under section 139(2).