This document contains draft text changes and an electronic attachment for an updated future edition of Rec. ITU-T H.266.2 | ISO/IEC 23090-16. The software codebase is more updated than that published by ITU-T as Rec. ITU-T H.2662 v2 (06/24) and is prepared for a next Rec. ITU-T H.2662 v3 or Ed. 2 of ISO/IEC 23090-16. Compared to the reference source code of the first edition of Rec. ITU-T H.266.2, this revision includes software implementation of additional SEI messages defined in Rec. ITU-T H.266 | ISO/IEC 23090-3 and in Rec. ITU-T H.274 | ISO/IEC 23002-7, as well as general software improvements such as bug fixes, run time improvements, additional encoder configuration options, and modified encoder configuration files yielding improved compression performance.