The Secretaría de Economía (SE) of Mexico released the Norma Oficial Mexicana NOM-008-SE-2021 in the Diario Oficial de la Federación (DOF) on December 29, 2023. This new NOM repeals NOM-008-SCFI-2002 and sets definitions, symbols, and writing rules for units of the General System of Measurement Units. These rules apply to magnitudes describing properties of bodies, phenomena, or physical, chemical, or biological substances, regardless of their use across fields such as science, technology, environment, education, health, and commerce. The NOM will take effect 180 days after its DOF publication, on June 26, 2024.