This is not correct. You are the one that has to maintain your server. We provide you the Cloud Image so you can deploy very easy MedaWiki on Azure this application with everything already configured (App, Web Server, Database, etc.). We also release periodically new versions of this image whenever Medawiki or any of the components (Apache, PHP, MySQL, etc.) have a new version or they are affected by a security issue. However, you are the one in charge of moving your data to the new version of the Image whenever a new version is released in order to maintain your site secure and updated. This will be the workflow:
1) You launch a server (server A) with latest version of Mediawiki and you create your site.
2) We publish a new version of Mediawiki with a new version of Apache that fixes a security issue.
3) You launch a server with the new version of Mediawiki which fixes the issue (server B).
4) You migrate your data from A to B.
5) You removed server A. Now everything is updated and secure on server B.