Vehicles of categories M₁, N, O, R, S and T may fall out of scope of UN R155 or UN R156 if they lack ECUs or do not permit software updates. Approval authorities currently make individual determinations regarding whether vehicles are in or out of scope, and justification for out-of-scope decisions must be recorded to ensure vehicles remain out of scope during the lifetime of whole vehicle approval. UN Regulation No. 10 provides precedent by allowing approvals for vehicles where certain equipment is not relevant. A similar provision could be incorporated into UN R155 and UN R156 by amending the scope and adding provisions to section 5 allowing manufacturers to obtain approvals for vehicles that do not permit software updates, with requirements of paragraph 7 not applying.