The MDR transition periods are the most amended, most extended, and most misunderstood part of the regulation. The original 2017 text set ambitious timelines for transitioning from the old MDD to the new MDR. Reality intervened. COVID-19, the Notified Body bottleneck, and the sheer scale of the transition forced the European Commission to extend the deadlines significantly through Regulation (EU) 2023/607.

For startups in 2026, the critical question is: what deadlines are still active, what has already passed, and how do the transition provisions affect your regulatory strategy?

What Were the Original Transition Provisions?

The MDR (adopted in 2017) included transition provisions in Article 120 that allowed devices certified under the old MDD (93/42/EEC) and AIMDD (90/385/EEC) to remain on the market under certain conditions:

Original Article 120(2): Devices with valid MDD/AIMDD certificates could continue to be placed on the market until the certificate expired, but no later than May 27, 2024. After that date, they could be made available on the market (i.e., remain in the supply chain) until May 27, 2025 .

These timelines were already extended once when the MDR's date of application was pushed from May 2020 to May 2021 due to COVID-19.

But the real problem was Notified Body capacity. By 2022, it was clear that thousands of devices would lose their market authorization. Not because they were unsafe, but because there were not enough Notified Bodies to process the MDR recertification applications in time. The European Commission acted.

What Did Regulation (EU) 2023/607 Change?

Regulation (EU) 2023/607, adopted on March 20, 2023 , amended Article 120 to extend the transition periods significantly. The key changes:

Extended Sell-Off Deadlines (New Article 120(2))

Devices legally placed on the market under the old MDD/AIMDD before May 26, 2021. Or devices placed on the market from May 26, 2021, based on valid MDD/AIMDD certificates. Can continue to be made available on the market or put into service, subject to the following deadlines:

For Class III and Class IIb implantable devices: Until December 31, 2027 .

For Class IIb (non-implantable), Class IIa, and Class I devices requiring Notified Body involvement (sterile, measuring): Until December 31, 2028 .

For Class I devices not requiring Notified Body involvement: These deadlines generally do not apply in the same way, as Class I devices transitioned directly upon the MDR's date of application .

Conditions for Using the Extended Deadlines

The extended transition periods are not automatic. Manufacturers must meet specific conditions to benefit from them :

  1. The device must continue to comply with the MDD or AIMDD. The device cannot be modified in a way that changes its safety or performance profile beyond what was covered by the original MDD/AIMDD certificate.

  2. No significant changes in design or intended purpose. If the manufacturer makes significant changes to the device's design or intended purpose, the MDD/AIMDD certificate no longer covers the modified device, and the transition provision no longer applies.

  3. No unacceptable risk. The device must not present an unacceptable risk to health or safety of patients, users, or other persons.

  4. The manufacturer must have applied to a Notified Body for MDR conformity assessment. The manufacturer must have submitted an application before a defined deadline .

  5. Written agreement with a Notified Body. The manufacturer and the Notified Body must have signed a written agreement for the MDR conformity assessment by September 26, 2024 .

  6. QMS requirements. The manufacturer must have in place a quality management system in accordance with Article 10(9) of the MDR .

Removal of the "Sell-Off" Deadline

The original Article 120(4) imposed a "sell-off" deadline. After the transition period expired, devices already in the distribution chain could only be made available for a limited additional period. The 2023 amendment removed this sell-off deadline for devices that benefit from the extended transition. Devices that meet the conditions above can be made available on the market until the new deadlines without a separate sell-off limitation .

What Does This Mean for Startups in 2026?

For startups building new devices, the transition provisions have limited direct application. They primarily affect legacy devices with existing MDD/AIMDD certificates. However, there are several scenarios where the transition periods affect your startup:

Scenario 1: You Are Developing a New Device

If your device has never been certified under the MDD or AIMDD, the transition provisions do not help you. You must go through the full MDR conformity assessment process. There is no MDD pathway available for new devices.

This has been true since May 26, 2021. Every new device placed on the market for the first time since that date must comply with the MDR.

Scenario 2: You Acquired a Company with Legacy Certificates

If your startup acquired or merged with a company that has existing MDD/AIMDD certificates, the transition provisions may allow you to continue selling those devices while you work on MDR certification. Provided the conditions are met (no significant changes, application to Notified Body, written agreement, QMS in place).

Check whether the previous manufacturer met the application and agreement deadlines. If they did not, the transition provisions may not apply, and the devices may need to be withdrawn from the market until MDR certification is obtained.

Scenario 3: You Are Building on a Legacy Platform

If your new device is based on technology from a legacy device that has MDD/AIMDD certification, the transition provisions apply to the legacy device. Not to your new device. Your new device requires its own MDR conformity assessment.

However, clinical data from the legacy device may support your MDR clinical evaluation, subject to the equivalence requirements in Article 61 .

Scenario 4: You Compete with Legacy Devices

The transition provisions allow your competitors' legacy devices to remain on the market until 2027 or 2028 without MDR certification. This creates a competitive dynamic where some devices on the market are certified under the old MDD and some under the new MDR. For your marketing, this is a potential differentiator. Your MDR-certified device demonstrates compliance with the higher standard.

What Deadlines Should You Watch?

December 31, 2027: Transition deadline for Class III and Class IIb implantable legacy devices. After this date, these devices must either have MDR certificates or be withdrawn from the market .

December 31, 2028: Transition deadline for Class IIb (non-implantable), Class IIa, and Class I (sterile/measuring) legacy devices .

Ongoing EUDAMED milestones: When EUDAMED is declared fully functional, new registration and reporting obligations will activate with a transition period.

Harmonized standards updates: New harmonized standards or withdrawal of existing harmonizations can change compliance expectations.

Will There Be Further Extensions?

As of early 2026, there is no formal announcement of further extensions beyond the 2027/2028 deadlines. However, the political and practical dynamics that led to the 2023 amendment. Notified Body capacity constraints and the risk of device shortages. Have not fully resolved.

Tibor's view is pragmatic: "Plan as if the deadlines are final. If they are extended again, that is a bonus. If they are not, you are ready. The worst position is to assume another extension and then be caught without MDR certification when the deadline hits."

The Practical Takeaway

The transition periods are a grace period for legacy devices. They are not a grace period for new market entrants. If you are a startup building a new medical device in 2026, the MDR applies to you fully, today, without transition provisions.

For legacy devices in your portfolio (through acquisition or partnership), verify that all conditions for the extended transition are met. Application deadlines, written agreements, QMS compliance, no significant device changes. Missing any condition invalidates the transition benefit.

And for your overall regulatory strategy: do not wait for the deadlines. The Notified Body backlog that caused the original extensions is still a factor. The earlier you start your MDR conformity assessment, the more control you have over your timeline.

This post concludes our first series on MDR Fundamentals. For the next topic. The amendment regulation itself. Read The MDR Amendment (EU) 2023/607: Extended Transition Periods for Legacy Devices.