Service of notice: prescribed methods for delivering GST communications and rules governing deemed receipt. Section 169 prescribes that GST communications may be served directly to the taxable person or authorised representative, by registered post/speed post/courier with acknowledgement to last known business or residence, by recorded email, by availability on the common portal, by local newspaper publication, or, if impracticable, by affixation at last known business or residence or on the issuing office notice board. Communications are deemed served on the date tendered, published or affixed; those sent by registered or speed post are deemed received after the normal postal transit period unless rebutted.