Update index.md

docs/index.md

@@ -105,11 +105,12 @@ scramv1 b clean; scramv1 b # always make a clean build
 
 ### Oustide of CMSSW (recommended for non-CMS users)
 
-Pre-compiled versions of the tool are available as container images from the [CMS cloud](https://gitlab.cern.ch/cms-cloud/combine-standalone/container_registry/15235). These containers can be downloaded and run using [Docker](https://cms-opendata-guide.web.cern.ch/tools/docker/). If you have docker running you can pull and run the *latest* image using, 
+Pre-compiled versions of the tool are available as container images from the [CMS cloud](https://gitlab.cern.ch/cms-cloud/combine-standalone/container_registry/15235). These containers can be downloaded and run using [Docker](https://cms-opendata-guide.web.cern.ch/tools/docker/). If you have docker running you can pull and run the image using, 
 
 ```sh
 docker run --name combine -it gitlab-registry.cern.ch/cms-cloud/combine-standalone:latest
 ```
+where you must replace `<tag>` with a particular version of the tool - eg - `v9.2.0`. See the top of this page for the latest recommended versions. 
 
 You will now have the compiled <span style="font-variant:small-caps;">Combine</span> binary available as well as the complete package of tool. 
 The container can be re-started using `docker start -i combine`.