Several updates and changes have been made to the Missouri Code of State Regulations governing modular units Chapter 123 – 20 CSR 4240-123. Prior approved existing modular units will be valid until May 30, 2025. Effective November 30, 2024, new codes were adopted, and all new modular unit models must be constructed to the criteria set forth in the 2021 International Building Code, the 2021 International Plumbing Code, the 2021 International Mechanical Code, the 2021 International Fuel Gas Code, the 2021 International Residential Code, the 2021 International Energy Code and the 2020 National Electric Code NFPA 70 NEC.