> For the complete documentation index, see [llms.txt](https://www.mica.wtf/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.mica.wtf/definitions/ai-act/substantial-modification.md).

# substantial modification

Definition of substantial modification from Regulation (EU) 2024/1689, Article 3, point (23).

|                  |                                            |
| ---------------- | ------------------------------------------ |
| **Defined term** | substantial modification                   |
| **Source**       | AI Act                                     |
| **Reference**    | Article 3, point (23)                      |
| **Status**       | Published                                  |
| **Refresh rule** | Regenerate after source legal-text changes |

## Definition

> (23) substantial modification means a change to an AI system after its placing on the market or putting into service which is not foreseen or planned in the initial conformity assessment carried out by the provider and as a result of which the compliance of the AI system with the requirements set out in Chapter III, Section 2 is affected or results in a modification to the intended purpose for which the AI system has been assessed;

## Source

[AI Act, Article 3, point (23)](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02024R1689-20240712).


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