Add Functions Versioning content

Author: rchinn1

src/connections/functions/environment.md

@@ -52,7 +52,60 @@ If you're editing an existing function, you can **Save** changes without changin
 
 When you deploy your destination function in your workspace, you fill out the settings on the destination configuration page, similar to how you would configure a normal destination.
 
+## Functions Versioning
 
+With Functions Versioning, you can access a complete change history for each source or destination function. View version history and creation details, then use a unified or split display to compare code and restore previous versions of a function.
+
+> info "Functions Versioning in Beta"
+> Functions Versioning is in beta, and Segment is actively working on this feature. Some functionality may change before it becomes generally available. [Contact Segment](https://segment.com/help/contact/){:target="_blank"} with any feedback or questions.
+
+### View and compare version history
+
+To view the version history of a function:
+1. Navigate to **Connections > Catalog > Functions**.
+2. Select your source or destination function.
+3. Select **Edit Function**, then click **Version history**.
+
+Select previous versions to compare code using a *unified* or *split* view. With the split view, Segment displays the latest version on the left, and the version you've selected on the right.
+
+> success ""
+> Unified and split compare screens are read-only. While you can copy code, you can't make changes directly from these screens.
+
+#### `LATEST` and `DEPLOYED` versions
+
+ In the Version History panel, Segment displays `LATEST` and `DEPLOYED` labels that represent a function version state. You'll see the `LATEST` version at the top.
+
+Segment labels a version as the `LATEST` when:
+- You save a change to the function source code, but don't deploy the function at the same time.
+- You [restore a previous version](#restore-a-previous-version) from your function's version history.
+
+The `DEPLOYED` version is the function version that's currently deployed.
+
+### Restore a previous version
+
+To restore a previous function version:
+
+1. Select the function you want to restore.
+2. Click **Restore this version**.
+  - Segment creates a duplicate of the selected version and labels it as the `LATEST` version.
+3. Click **Restore** on the confirmation screen.
+4. To deploy the restored version, click **Save and Deploy** on the Source Code screen.
+
+### Use Versioning with Segment's Public API
+
+You can use Functions Versioning with Segment's [Public API](https://docs.segmentapis.com/tag/Functions){:target="_blank"} to retrieve version history records and source code, as well as to restore previous versions.
+
+Here are some Public API use case examples:
+
+**Get Version history**: Use the `/versions` endpoint to retrieve a list of version records and metadata of a certain page size. You can also use this endpoint to get version source code for a given version ID.
+
+**Restore a previous version**: Use the `/restore` endpoint to restore a previous Function version. This creates a new version with the same source as the version you are restoring.
+
+**Create or update versions**: Create or update a function to add a version record and save the source code.
+
+**Deploy a function**: Use the Public API to deploy a function. After you deploy, Segment marks the function version as `DEPLOYED`. Learn more about [version states](#latest-and-deployed-versions).
+`
+View Segment's [Public API](https://docs.segmentapis.com/tag/Functions){:target="_blank"} docs for more information on how to use Functions Versioning with the Public API.
 
 ## Functions permissions