What is MDR Rule 11, and why does it make my software Class IIa?

In short: Rule 11 is the MDR classification rule for software. Software providing information used for diagnostic or therapeutic decisions is at least Class IIa — higher if those decisions could cause serious harm or death. In practice, Rule 11 makes Class I rare for medical software, which means Notified Body involvement.

What Rule 11 actually asks

MDR Annex VIII sets out 22 classification rules; Rule 11 is the one written specifically for standalone software, added to close a gap left by the old Medical Devices Directive, under which most software defaulted to low-risk Class I. Rule 11 asks what the software's output is used for and how significant that use is. Information that could lead to a decision causing death or irreversible deterioration is Class III. Information that could lead to serious deterioration or surgical intervention is Class IIb. Everything else providing diagnostic or therapeutic decision-support information defaults to Class IIa — the outcome for most clinical decision-support software, since most products fall in this middle band. Software monitoring physiological processes is Class IIa, unless it monitors vital parameters where variation could pose immediate danger, in which case it's Class IIb.

Why this closed the Class I shortcut

Before MDR, plenty of decision-support software self-certified as Class I. Rule 11 was written deliberately to prevent that default. The practical consequence: for software with any genuine clinical decision-support function, self-certification is no longer available, and a Notified Body — an organisation designated by an EU member state to assess conformity of medium- and higher-risk devices — must review your technical file before you can affix the CE mark.

What this means for sequencing

Once you have a reasonable-confidence Rule 11 read, the useful next move isn't waiting for certainty before starting anything — it's starting your quality management system and technical file build in parallel, since most of that foundation is class-agnostic. Founders who treat classification as a gate before "real" work begins routinely lose months they didn't need to lose.

A live proposal to change Rule 11 itself

Status as of 2 July 2026. The European Commission published a proposal on 16 December 2025 to simplify MDR and IVDR, including a revised Rule 11 with wider scope for software to land in Class I, or to move down from IIb to IIa, specifically for software that monitors or analyses data without driving autonomous high-stakes decisions. This is not yet law: it needs European Parliament and Council approval through the ordinary legislative procedure, with adoption anticipated at the earliest by summer 2026 and realistically more likely late 2026 or into 2027. Nothing about your classification changes today because of this proposal, but if you're building a multi-year regulatory roadmap around a Class IIa or IIb outcome, it's worth tracking — a rule change of this kind could shift your CE-marking cost and timeline materially by the time you'd actually be submitting.

Where next: MDR Rule 11: Why Software Lands in Class IIa · Is my software a medical device under EU MDR?

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