doc: Define upgrade guide for 1.40.0 release (#3604)

AgustinBettati · web-flow · commit 75e5388fdf26 · 2025-08-20T17:01:59.000+02:00
* move 1.18.0 and below into older guides section

* adding 1.40.0 migration guide
diff --git a/docs/guides/1.16.0-upgrade-guide.md b/docs/guides/1.16.0-upgrade-guide.md
@@ -1,5 +1,6 @@
 ---
 page_title: "Upgrade Guide 1.16.0"
+subcategory: "Older Guides"
 ---
 
 # MongoDB Atlas Provider 1.16.0: Upgrade and Information Guide
diff --git a/docs/guides/1.17.0-upgrade-guide.md b/docs/guides/1.17.0-upgrade-guide.md
@@ -1,5 +1,6 @@
 ---
 page_title: "Upgrade Guide 1.17.0"
+subcategory: "Older Guides"
 ---
 
 # MongoDB Atlas Provider 1.17.0: Upgrade and Information Guide
diff --git a/docs/guides/1.18.0-upgrade-guide.md b/docs/guides/1.18.0-upgrade-guide.md
@@ -1,5 +1,6 @@
 ---
 page_title: "Upgrade Guide 1.18.0"
+subcategory: "Older Guides"
 ---
 
 # MongoDB Atlas Provider 1.18.0: Upgrade and Information Guide
diff --git a/docs/guides/1.40.0-upgrade-guide.md b/docs/guides/1.40.0-upgrade-guide.md
@@ -0,0 +1,17 @@
+---
+page_title: "Upgrade Guide 1.40.0"
+---
+
+# MongoDB Atlas Provider 1.40.0: Upgrade and Information Guide
+
+The Terraform MongoDB Atlas Provider version 1.40.0 introduces the following new features and fixes:
+
+## New Resources, Data Sources, and Features
+
+- Adds support for S3 Private Link Endpoints in Atlas Stream Processing connections. To learn more, see the [resource documentation](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/stream_privatelink_endpoint) and [associated example](https://github.com/mongodb/terraform-provider-mongodbatlas/tree/master/examples/mongodbatlas_stream_privatelink_endpoint/s3).  
+
+## Helpful Links
+
+* [Report bugs](https://github.com/mongodb/terraform-provider-mongodbatlas/issues)
+* [Request Features](https://feedback.mongodb.com/forums/924145-atlas?category_id=370723)
+* [Contact Support](https://docs.atlas.mongodb.com/support/) covered by MongoDB Atlas support plans, Developer and above.
