Docs: Clarify "upgrade proceedure" for docker

docs/content/setup/docker.md

@@ -33,6 +33,10 @@ The Infection Monkey Docker container works on Linux only. It is not compatible
     ```
 
 ### 2. Start MongoDB
+{{% notice info %}}
+If you are upgrading the Infection Monkey to a new version, be sure to remove
+any MongoDB containers or volumes associated with the previous version.
+{{% /notice %}}
 
 1. Start a MongoDB Docker container:
 
@@ -62,6 +66,10 @@ been signed by a private certificate authority.
     ```
 
 ### 3b. Start Monkey Island with user-provided certificate
+{{% notice info %}}
+If you are upgrading the Infection Monkey to a new version, be sure to remove
+any volumes associated with the previous version.
+{{% /notice %}}
 
 1. Create a directory named `monkey_island_data`. If you already have it,
    **make sure it's empty**. This will serve as the location where Infection
@@ -132,13 +140,9 @@ After the Monkey Island docker container starts, you can access Monkey Island by
 ## Upgrading
 
 Currently, there's no "upgrade-in-place" option when a new version is released.
-To get an updated version, download it, stop the current container and run the
-installation commands again with the new file.
-
-If you've configured Monkey Island to use a docker volume to store runtime data,
-make sure that it is empty before upgrading the Infection Monkey. Also make sure
-that you use a clean volume for MongoDB, as database schemas may not be compatible
-between different versions of the Infection Monkey.
+To get an updated version, download it, stop and remove the current Monkey
+Island and MongoDB containers and volumes, and run the installation commands
+again with the new file.
 
 If you'd like to keep your existing configuration, you can export it to a file
 using the *Export config* button and then import it to the new Monkey Island.