26. The expert from TF TPMSTI presented further amendments to UN Regulation No. 141 that introduced an alternative procedure for type approval of trailers (vehicles of categories O3 and O4), regarding their Tyre Pressure Monitoring System (TPMS), Tyre Pressure Refilling System (TPRS) and Central Tyre Inflation System (CTIS) (ECE/TRANS/WP.29/GRBP/2021/20). GRBP adopted these proposals, as amended by GRBP-74-37, and requested the secretariat to submit them for consideration and vote at the March 2022 sessions of WP.29 and AC.1 as part of draft Supplement 1 to the 01 series of amendments to UN Regulation No. 141.