> For the complete documentation index, see [llms.txt](https://docs.adaptiva.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.adaptiva.com/patch/advanced-settings/chains.md).

# Chains - Approval and Notification

Overview of approval and notification chains

OneSite Patch uses Approval Chains and Notification Chains to communicate and seek approvals for patch updates and installations.

![](https://2503798551-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F7VJNM00p5XQ4pMWqCu8y%2Fuploads%2Fgit-blob-8decd114ffd017dda0a9b237fc6610ec6082d220%2Fside-navigation.png?alt=media)

* [Approval Chains](/patch/advanced-settings/chains/chains-approval.md) define who will be able to approve patch installations, including details such as approval layers, backup roles, reminder intervals, and more.
* [Notification Chains](/patch/advanced-settings/chains/chains-notification.md), used only in Advanced Strategies, define who will be notified of patch installations, based on role membership.

You assign chains to a Patching Strategy, a Business Unit, or a Deployment Channel.