After the Update System is still showing the Old OS After the Update System is still showing the Old OS check the screenshot

 

and if i click on the system update there is no os update just some other updates.check the screenshot

please help me out
This happens to me occasionally—after installing the latest update my iMac reboots and it’s still running its previous version. I just run the update again, then everything updates correctly.

Just download and install the latest macOS Sierra Update image from Apple. As of June 6th, 2017, that would be 10.12.5.