Service of notice ensures validity of communications and prescribes multiple modes and deemed receipt rules. Section 169 sets out permitted modes for serving notices and communications-direct service (including messenger), registered post/speed post/courier with acknowledgement, email to the registration address, availability on the common portal, publication in a local newspaper, or affixation where other modes are impracticable-and provides that communications are deemed served on the date they are tendered, published, or affixed, while those sent by registered or speed post are deemed received after the normal transit period unless contrary proof is provided.