This paper is to inform relevant GRs of the ongoing activities within the CLIV informal group and the potential influence on the work under the responsibilities of the GRs. CLIV is in Phase 2 developing a new UN Regulation on Children Left in Vehicles for vehicle categories M₁, M₂, M₃ and N₁. The draft regulation includes requirements for visual and audible external warnings upon detecting a CLIV event. The IWG prioritises development for buses first, then light vehicles. The draft regulation aims to mitigate risk of serious or fatal injuries to children left in vehicles. Upon detecting a CLIV event, visual and audible external warnings will be generated using an SOS morse code pattern to distinguish from existing warnings.