Add explicit instructions for older docker-compose files.

docs/docs/content/upgrade.md

@@ -14,11 +14,22 @@ If you installed listmonk as a service, you will need to stop it before overwrit
 If it's not running as a service, `pkill -9 listmonk` will stop the listmonk process.
 
 ## Docker
-> Instructions for versions above v4.x.x using the latest [docker-compose.yml](https://github.com/knadh/listmonk/blob/master/docker-compose.yml) file.
+**Important:** The following instructions are for the new [docker-compose.yml](https://github.com/knadh/listmonk/blob/master/docker-compose.yml) file for v4.x.x onwards.
+
+```shell
+docker compose down app
+docker compose pull
+docker compose up app -d
+```
+
+If you are using an older docker-compose.yml file (versions older than v4.x.x), you have to run the `--upgrade` step manually.
+
+```shell
+docker-compose down
+docker-compose pull && docker-compose run --rm app ./listmonk --upgrade
+docker-compose up -d app db
+```
 
-- `docker compose down app` and stop the app container.
-- `docker compose pull` to pull the latest version from DockerHub.
-- `docker compose up app -d` to automatically run the upgrade and start listmonk.
 
 ## Railway
 - Head to your dashboard, and select your Listmonk project.