UNECE R156
The UN regulation on software updates — manufacturers must run a certified software update management system and keep updated vehicles compliant.
UNECE Regulation No. 156 is the UN regulation governing software updates to vehicles. It requires manufacturers to operate a certified Software Update Management System (SUMS): documented processes proving that every update — over-the-air or in the workshop — is assessed for safety and regulatory impact, that vehicles remain type-approval compliant after updating, and that the software version running in any vehicle can be identified via defined software identification numbers (RXSWIN).
R156 was adopted alongside R155 in 2020 and follows the same EU timeline: mandatory for new vehicle types from July 2022 and for all new registrations from July 2024, with parallel adoption in Japan and South Korea.
The regulation is the legal backbone of the OTA era. It forces the update pipeline to be an auditable engineering system rather than an IT convenience — and it is the reason “can we ship this feature by OTA” is partly a homologation question, not just a technical one.
Related: OTA update · Type approval / homologation · UNECE R155