Since their publication in 1950s and 1980s, respectively, the Commentaries on the Geneva Conventions of 1949 and their Additional Protocols of 1977 have become a major reference for the application and interpretation of these treaties. The International Committee of the Red Cross (ICRC), together with a team of renowned experts, is currently updating these Commentaries in order to document developments and provide up-to-date interpretations. The work on the first updated Commentary, the Commentary on the First Geneva Convention relating to the protection of the wounded and sick in the armed forces, has already been finalized. This article provides an overview of the methodology and process of the update and summarizes the main evolutions in the interpretation of the treaty norms reflected in the updated Commentary.