# Updating archetype of a composition

**Category:** [RM](https://discourse.openehr.org/c/rm/42)
**Created:** 2021-08-19 13:00 UTC
**Views:** 524
**Replies:** 1
**URL:** https://discourse.openehr.org/t/updating-archetype-of-a-composition/1789

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## Post #1 by @Jelte

We are looking into updating existing compositions to use a new version of an archetype.

However the [VERSIONED_COMPOSITION](https://specifications.openehr.org/releases/RM/latest/ehr.html#_versioned_composition_class) class has this invariant:

> *Archetype_node_id_valid*: `for_all v in all_versions | v.archetype_node_id.is_equal (all_versions.first.archetype_node_id)`

And the archetype_node_id [should contain the stringified archetype_id](https://specifications.openehr.org/releases/RM/latest/common.html#_locatable_class):

> At an archetype root point, the value of this attribute *[archetype_node_id]* is always the stringified form of the `archetype_id` found in the `archetype_details` object.

This seems to imply that the archetype_id (including the version number) cannot change between composition versions.

Is my understanding of this constraint correct, i.e. is updating the archetype of a composition currently not allowed?

If so, should this be allowed? I think it is valid for long-lived (e.g. `persistent` and `episodic`) compositions to be migrated to a new archetype version. For example, when a new field is added it should become usable in existing compositions.

What do you think?

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## Post #2 by @thomas.beale

Jelte,
We are now discussing this issue in [SPECPR-373](https://openehr.atlassian.net/browse/SPECPR-373).

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**Canonical:** https://discourse.openehr.org/t/updating-archetype-of-a-composition/1789
**Original content:** https://discourse.openehr.org/t/updating-archetype-of-a-composition/1789