28. [The GRPE Chair] announced that the IWG on Vehicle Propulsion System Definitions (VPSD) would submit a formal proposal for a new Mutual Resolution on Vehicle Powertrain Definitions for the June 2015 session of GRPE.

29. He introduced the informal documents, which list the acronyms and abbreviations used in UN Regulations (WP.29-165-17) and highlighted the problem of using the acronym ‘RESS’ to describe both the ‘Non-original Replacement Exhaust Silencer System’ and the ‘Non-original Replacement Exhaust System and Rechargeable Energy Storage System’ (WP.29-165-16). The World Forum endorsed the content of document WP.29-165-16 and referred the choice to its subsidiary bodies. The secretariat added that the document WP.29-165-17 would be made available on the UNECE website and it would continue to be updated on a regular basis.