Software Update Management System (SUMS) Policy

Document No.: POL-02 · Revision: 00 · Effective: October 2026 · Approved by: General Manager

At STU Treyler, we are committed to managing the software on our vehicles, and every update to it, so that vehicle safety, cyber security and conformity with the type approval are maintained throughout the life of the vehicle. To this end we have established a Software Update Management System (SUMS) that meets the requirements of UN Regulation No. 156 (R156).

Purpose and scope

This policy covers all software-based electronic control units and systems on the category O3 and O4 semi-trailers and trailers manufactured and type-approved by STU. The main examples are EBS/TEBS brake control modules, lift-axle and suspension controls and — where fitted — hydraulic control units, remote controls, tyre-pressure monitoring and telematics systems.

The scope includes software installation and parameter setting on the production line as well as every software or parameter update carried out after the vehicle has been registered.

Our commitments

1. Management responsibility: We provide the resources needed to establish, implement and maintain the SUMS. A SUMS manager has been appointed, and all roles, authorities and responsibilities are defined in writing.
2. Software configuration records: For every vehicle we record, by vehicle identification number (VIN), the hardware and software versions, the parameter sets and their change history.
3. RXSWIN management: For type-approval-relevant software we define Regulation X Software Identification Numbers (RXSWIN), link them to each software version and keep them up to date and readable from the vehicle or from our records.
4. Impact assessment: Before every update we assess and record its effect on the type approval, on vehicle safety, on dependencies with other systems and on compatibility with the configuration of the target vehicles. We do not apply an update that affects the type approval without the required approval from the approval authority.
5. Identification of target vehicles: We use our records to identify precisely the vehicles to which an update applies, and we ensure that an update is applied only to vehicles with a compatible configuration.
6. Software integrity and cyber security: We use only software obtained from authorised suppliers whose integrity and authenticity have been verified. Access to update tools and files is limited to authorised staff, and the update process is protected against unauthorised modification and misuse.
7. Safe execution: Updates are carried out only by trained staff or authorised service partners, with the vehicle safely parked and secured. We verify that each update has been completed successfully; if an update fails or is interrupted, the vehicle is returned to the previous version or to a safe state.
8. Informing users: We inform vehicle owners and users before and after an update about its purpose, its effect on the vehicle, any action required and any restrictions on use.
9. Supplier management: We have arrangements with the suppliers of software-based components that ensure the sharing of information on software versions, updates, vulnerabilities and RXSWIN.
10. Over-the-air (OTA) updates: On our current products, software updates are carried out at an authorised workshop through a diagnostic connection. Should OTA updating be introduced, the additional R156 requirements for OTA updates will be met before it is put into use.
11. Records and transparency: We keep the records of the SUMS processes and of every update for the period required by law, and make them available in full to the approval authority and the technical service on request.
12. Competence and continual improvement: We train the staff concerned in the SUMS processes, and we evaluate and continually improve the effectiveness of the system through internal audits and management reviews.

This policy complements our Quality Policy. It has been approved by top management, is communicated to all employees and suppliers concerned, is made publicly available on our website and is reviewed at least once a year or whenever the regulations change.

STU Treyler Dorse İthalat İhracat Ltd. Şti. — General Manager