# Versioning
URL: https://docs.awellhealth.com/docs/extensions/versioning

> For the complete documentation index, see [llms.txt](https://docs.awellhealth.com/llms.txt).



Every extension carries a changelog, declared as part of its
[required folder structure](/docs/extensions/create-an-extension).

## The changelog is how installers learn what changed [#the-changelog-is-how-installers-learn-what-changed]

An extension is installed by other people, often in more than one environment, and its
[settings](/docs/extensions/extension-settings) are configured per installation. When behavior changes,
the changelog is how an installer finds out.

For a public extension on the [Marketplace](/docs/marketplace), it's read by customers deciding whether
an update is safe to take.

## Record anything an installer has to act on [#record-anything-an-installer-has-to-act-on]

* a new or removed action
* a new required setting, which will break existing installations until configured
* a change in what an action returns, since care flows may store it as data points
* a fix that changes observable behavior

A new required setting is the one to be loudest about, since every existing installation needs attention.

> **This page is thinner than it should be.** The source it came from is a placeholder, so the mechanics
> of how extension versions are numbered, published and pinned are not documented yet. Email
> [support@awellhealth.com](mailto:support@awellhealth.com) in the meantime.

## Next steps [#next-steps]

**Next:** [Contributing guidelines](/docs/extensions/contributing-guidelines) for a public extension.