Proposal to amend UN GTR No. 25 by modifying requirements for State-of-Certified Energy (SOCE) monitors, battery performance requirements, in-use verification procedures for Parts A, B, and C, and related test procedures and annexes. The GTR establishes harmonised methods to determine in-vehicle battery durability performance of Heavy-Duty Pure Electric Vehicles (HD-PEVs) and Heavy-Duty Off-Vehicle Charging Hybrid Electric Vehicles (HD-OVC-HEVs) of categories 1-2 and 2 exceeding 3,855 kg technically permissible maximum laden mass. The document includes tracked changes to Amendment 1 (WP.29/2026/209), with sections subject to discussion or decision indicated in square brackets and strikethrough text denoting proposed deletions.