Proposal to enable approval of an Enhanced Child Restraint System (ECRS) with a module that is, or can be, converted into a booster seat or an ECRS with a module of a vehicle-specific application and to remove the prohibition on use of the Unique Identifier per the WP.29 decision to change the default application of the UI from a requirement (requiring prohibition in cases where UI does not apply) to a permission (requiring an affirmative statement that UI may be used under a Regulation).