With recent versions of SCCM, you can now perform in-place updates of SCCM. This is a great way of updating the application without having to download external ISOs etc.
The only issue is that once you have kicked off the install, you have no way of monitoring the progress within the application itself. We have to move to the LOG files in order to monitor this.
You can see the update highlighted here:
If you right-click the update, you can see "Install Update Pack".
Once you have done this, the only way to monitor the progress is by opening up the following LOG file within CMTrace:
C:\Program Files\Microsoft Configuration Manager\Logs\CMUpdate.log
This will update automatically as there's new information, and it's an easy way to see where the installation is at and whether there's any problems.