Microsoft does not deliver all updates to WSUS, especially those missing that do not seem particularly urgent. However, they can be manually imported into the WSUS server. As using Internet Explorer does not work all too often, you can use PowerShell instead. To import updates, the WSUS console provides a command in the context menu of the server. If you execute it, it launches the web browser and loads the start page of the Microsoft Update Catalog, where you can search for the desired updates.
