Deemed invalidation of courier registration after one year inactivity permits renewal application within a specified period subject to eligibility. Registration remains valid until revoked but is deemed invalid if an Authorised Courier is inactive for a continuous year (excluding suspension), with that year computed from the 2021 amendment. After deemed invalidation, the courier may apply in Form K within ninety days and pay the prescribed fee; renewal may be granted within one month if the authority is satisfied about satisfactory performance, absence of misconduct including non-compliance with regulation 12, and overall eligibility under regulation 10.