Microsoft has released KB4103720 cumulative update for Windows 10 Version 1607 (Anniversary Update). After installing this update, the complete build number of Windows will become 14393.2273. You can check the current build number of your Windows Operating System by going to Run –> winver.
These links have been taken from Microsoft Update catalog.
Before installing KB4103720 update
Before installing any Windows Update, it is always recommended to create a restore point for your safety.
Create a restore point
This should be the default case before installing any update or software on your system. At the very least, if the system get bricked after installing an update, you will be able to revert back to the working point.
To create a restore point, go to Run –> systempropertiesadvanced.
On the System Protection tab, enable System Restore and create a restore point manually.
Installing the update manually
If you are having issues while installing KB4103720 through Windows Update, most of the times, the issue is resolved when you restart your computer, download the update manually from above mentioned links and then install them manually.