Use the legal threshold
Article 4(18) first looks to relevant EU or national product-safety rules. Where those rules provide no threshold, the Directive supplies a test involving changes to original performance, purpose or type not foreseen in the initial risk assessment, together with a change in hazard or risk. Both parts of that fallback test matter.
Separate modification from ordinary maintenance
Repair, refurbishment, software changes and remanufacturing are descriptive activities. Whether a specific change is substantial requires the applicable threshold and facts. Do not use a universal percentage, component count or software-version rule to replace that analysis.
Record control and return to market
Article 8(2) also asks whether modification occurred outside manufacturer control and whether the modified product was subsequently made available or put into service. Preserve authorisation, changed functions and the relevant date. Article 17 addresses the expiry-period starting point for substantially modified products.
Records that help the review
Use the following as a practical starting point. Select and preserve records appropriate to the product, incident and applicable procedure.
- Before and after specifications
- Original risk assessment and intended function
- Relevant product-safety threshold
- Authorisation and post-change market records
No universal substantial-modification checklist applies to every product and jurisdiction.
Primary sources and legal scope
This page explains the EU Directive framework. Check national implementing law, the corrected temporal scope and relevant procedure before applying it to a case.
- Directive (EU) 2024/2853, consolidated text: Articles 4, 8, 11, 17 ↗
- Official Journal corrigendum, 7 May 2026: Article 2(1) ↗
Source register: corrected scope verified 16 October 2026. Article references identify the legal basis. No qualified legal review or national implementation status is claimed.