(DOCSP-6867): Tutorial to upgrade mdb version/fcv (#84)

* (DOCSP-6867): Tutorial to upgrade mdb version/fcv

* adding cm ui

* Updates per Nick's feedback

* Updates per Nick's feedback

Author: jeff-allen-mongo

source/tutorial/edit-deployment.txt

@@ -53,3 +53,10 @@ Procedure
 
    - You can set some settings using |k8s-op-short| only. To review the
      list of settings, see :doc:`/reference/k8s-op-exclusive-settings`.
+
+
+.. toctree::
+   :titlesonly:
+   :hidden:
+
+   /tutorial/upgrade-mdb-version

source/tutorial/upgrade-mdb-version.txt

@@ -0,0 +1,95 @@
+===============================
+Upgrade MongoDB Version and FCV
+===============================
+
+.. default-domain:: mongodb
+
+You can upgrade the major, minor, and/or feature compatibility versions
+of your MongoDB resource. These settings are configured in your
+resource's |k8s-configmap|.
+
+- To upgrade your resource's major and/or minor versions, set the
+  :setting:`spec.version` setting to the desired MongoDB version.
+
+- To modify your resource's 
+  :manual:`feature compatibility version
+  </reference/command/setFeatureCompatibilityVersion/>`, set
+  the :setting:`spec.featureCompatibilityVersion` setting to the desired
+  version.
+
+.. note::
+
+   If you update ``spec.version`` to a later version, consider setting
+   :setting:`spec.featureCompatibilityVersion` to the current working
+   MongoDB version to give yourself the option to downgrade if
+   necessary.
+
+   To learn more about feature compatibility, see
+   :dbcommand:`setFeatureCompatibilityVersion` in the MongoDB Manual.
+
+Example
+-------
+
+Consider the following |k8s-configmap| for a standalone resource:
+
+.. code-block:: yaml
+   :emphasize-lines: 7
+
+   ---
+   apiVersion: mongodb.com/v1
+   kind: MongoDB
+   metadata:
+     name: my-standalone-downgrade
+   spec:
+     version: 3.6.12
+     type: Standalone
+     project: my-project
+     credentials: my-credentials
+     persistent: false
+   ...
+
+This resource has a MongoDB version of ``3.6.12``. The following steps
+upgrade the deployment's MongoDB version to ``4.0.6``:
+
+1. Perform the following modifications to the resource's
+   ConfigMap:
+   
+   a. Set :setting:`spec.version` to the desired MongoDB version.
+   
+   #. Set :setting:`spec.featureCompatibilityVersion` to the current
+      working MongoDB version:
+
+   .. code-block:: yaml
+      :emphasize-lines: 7-8
+
+      ---
+      apiVersion: mongodb.com/v1
+      kind: MongoDB
+      metadata:
+        name: my-standalone-downgrade
+      spec:
+        version: 4.0.6
+        featureCompatibilityVersion: 3.6
+        type: Standalone
+        project: my-project
+        credentials: my-credentials
+        persistent: false
+      ...
+
+   .. note::
+
+      Setting ``featureCompatibilityVersion`` to ``3.6`` disables
+      :manual:`4.0 features that persist data incompatible with MongoDB 3.6
+      </release-notes/4.0-compatibility/#compatibility-enabled>`.
+
+2. Reapply the configuration to |k8s|:
+
+   .. code-block:: none
+
+      kubectl apply -f <standalone-config>.yaml
+
+|k8s| automatically reconfigures your deployment with the new
+specifications. You can see these changes reflected in the
+|mms| or `Cloud Manager <docs.cloudmanager.com/current/>`__
+:abbr:`UI (User Interface)`.
+