Add update procedure (#563)

* Add update procedure

* Undo formatting

* Remove substeps

* Apply suggestions from code review

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* Fix step

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

mkdocs.yml

@@ -175,6 +175,7 @@ nav:
       - docs/use/troubleshooting/logs.md
       - docs/use/troubleshooting/hacs_update_broke_my_hacs.md
       - docs/use/troubleshooting/ha_update_broke_my_hacs.md
+    - docs/use/update.md
     - docs/use/remove.md
   - Publish:
     - docs/publish/index.md

source/docs/use/update.md

@@ -0,0 +1,33 @@
+---
+title: Update HACS
+description: "Step-by-step instructions on updating HACS"
+---
+
+As soon as a new version of HACS is available, you'll receive an update notification in Home Assistant, just like with any other integration.
+
+## Updating HACS
+
+Follow these steps to update HACS itself. Updating HACS does not automatically update the repositories you have downloaded from HACS.
+
+1. [Create a backup](/docs/use/data.md/#creating-a-backup) and download that backup to another device.
+2. In Home Assistant, go to <!-- hacs:my updates title="**{{coreui('panel.config')}}** > **{{coreui('ui.panel.config.updates.caption')}}**" -->.
+    - Select the **HACS update** notification and check the release notes for backward-incompatible changes.
+    - If you're sure you want to update, select **Install**.
+3. [Restart Home Assistant](https://www.home-assistant.io/docs/configuration/#reloading-the-configuration-to-apply-changes).
+
+## Updating repositories
+
+Each repository represents an independent open-source project maintained by someone from the community. Each repository therefore has its very own update cycle.
+HACS [regularly checks the repositories for updates](/docs/faq/data_sources.md/#updates). This means that the list of repositories is regularly updated, there is no need for you to keep track of this.
+
+However, if you want to immediately check if something has changed for a repository, you can manually check for an [update of the repository metadata](/docs/use/repositories/dashboard.md/#updating-repository-metadata).
+
+## To update a downloaded repository
+
+These steps assume that you have already downloaded a repository. Follow these steps to update to a new software version of this repository.
+
+1. [Create a backup](/docs/use/data.md/#creating-a-backup) and download that backup to another device.
+2. If you have already downloaded a repository, you will get an update notification under <!-- hacs:my updates title="**{{coreui('panel.config')}}** > **{{coreui('ui.panel.config.updates.caption')}}**" -->.
+    - Open the notification and read the release notes.
+    - Select **Install**.
+3. If the repository is an integration, [restart Home Assistant](https://www.home-assistant.io/docs/configuration/#reloading-the-configuration-to-apply-changes).