Article 120(3) of the Medical Device Regulation (EU) 2017/745 (MDR), last amended by Regulation (EU) 2023/607, states that devices which continue to comply with the AIMDD or MDD may be placed on the market or put into service until 31 December 20271 or 31 December 20282  as applicable, provided the conditions set out in Article 120(3c) MDR are fulfilled.

These devices are called ‘legacy devices’ and in line with MDCG Guidance Document 2021-253 ‘legacy devices’ should be understood as devices, which, in accordance with the MDR’s transitional provisions, are placed on the market after the MDR’s date of application (i.e. 26 May 2021) if certain conditions are fulfilled. Those devices can be: 

 devices which are class I devices under Directive 93/42/EEC (MDD), for which an EC declaration of conformity was drawn up prior to 26 May 2021 and for which the conformity assessment procedure under the MDR requires the involvement of a notified body;
 devices covered by a valid EC certificate issued in accordance with Directive 90/385/EEC (AIMDD) or the MDD prior to 26 May 2021.4
The conditions are set out in Article 120(3c) MDR and include, among others, that legacy devices must continue to comply with the AIMDD/MDD5 , as applicable, and that there are no significant changes in the design or intended purpose of the device

. Therefore, it is important for manufacturers and notified bodies to have a clear understanding as to what changes to design or intended purpose would be considered ‘significant’.


It is essential for legacy devices that their certificates remain valid following changes that are not significant with regard to design or intended purpose and that the required appropriate surveillance is carried out .
The first revision of this guidance document MDCG 2020-3 on significant changes regarding the transitional provisions under Article 120(3) MDR takes into account the experience gained with the application of the original version so far, is aligned with the equivalent guidance for IVDs,  MDCG 2022-6 of May 20229 and adjusted to Regulation (EU) 2023/607.


This guidance document is intended to provide clarification on the concept of ‘significant changes in the design and intended purpose’ under Article 120(3c), point (b) MDR. It concerns manufacturers of legacy devices. 
This guidance document does not elaborate on the process for manufacturers’ submission and notified bodies’ assessment of changes to the approved design10 or substantial changes to the approved quality system or the product-range covered.