Appellate Authority under GST prescribes tiered appeal routes and distinct time limits for taxpayers and officers. Rule 109A designates appellate forums under GST: aggrieved persons may appeal to the Commissioner (Appeals) if the order was passed by an Additional or Joint Commissioner, or to an officer not below the rank of Joint Commissioner (Appeals) if passed by a Deputy/Assistant Commissioner or Superintendent, within three months of communication. Officers directed to appeal may file similar appeals within six months of communication, following the same rank-based allocation of appellate authorities.