UN Regulation No. 156 — Software Update and Software Update Management System

What UNECE R156 Is

UN Regulation No. 156, adopted under UNECE WP.29 alongside R155, requires vehicle manufacturers to implement a Software Update Management System (SUMS) and to deliver vehicle software updates safely and securely, including over-the-air (OTA) updates. It exists because software-defined vehicles increasingly receive functionality and security fixes after sale, and a flawed or malicious update can compromise safety. Like R155, R156 is tied to vehicle type approval in adopting markets.

R156 ensures that updates are authentic, traceable, and do not unintentionally break safety-relevant functions or regulatory compliance.

Who It Applies To

R156 applies to vehicle manufacturers seeking type approval in UNECE contracting parties that have adopted the regulation, including the EU, Japan, and South Korea. It covers vehicles capable of receiving software updates, with particular focus on OTA-capable vehicles, and it extends practical obligations to suppliers that provide updatable software components.

Key Requirements

• SUMS — Establish and certify a software update management system covering processes, roles, and records.
• Configuration awareness — Track hardware and software configurations and dependencies for each vehicle type.
• Update integrity and authenticity — Protect updates against tampering and verify their source before installation.
• Safe deployment — Assess update impact on safety and regulatory compliance, and ensure safe installation conditions and rollback where needed.
• OTA-specific controls — For over-the-air updates, inform users, ensure the vehicle is in a suitable state, and confirm successful installation.
• Documentation — Maintain records linking updates to vehicle types and outcomes.

Penalties for Non-Compliance

Without a valid SUMS certificate, manufacturers cannot obtain type approval and therefore cannot sell affected vehicles in adopting markets. Authorities can suspend or withdraw approvals, and faulty updates may trigger recalls and liability. The commercial impact of lost market access is the dominant deterrent.

How to Comply

Build a certifiable SUMS with rigorous configuration management so the organization always knows what software runs on each vehicle type. Sign updates and verify integrity and authenticity end to end, and design safe installation, including preconditions and rollback. For OTA, provide clear user communication and confirm installation success. Coordinate with suppliers and maintain documentation that supports type approval and audits.