This report describes the secretariat’s activities relating to the technical expert review of biennial transparency reports in the reporting period 1 January 2024 to 31 October 2025. It provides an update on the status of submissions of first biennial transparency reports and the reviews thereof; an overview of the training of technical expert reviewers and meetings of lead reviewers; and information on voluntary reviews of information on climate change impacts and adaptation, simplified reviews, and reviews of technical analyses of activities set out in paragraph 70 of decision 1/CP.16. Furthermore, the report presents challenges encountered by the secretariat, Parties and expert reviewers in conducting the reviews.