In some cases this update causes a problem regarding WiFi connectivity.
After the device gets updated, WiFi network can be connected but Internet doesn't work.
So here's the solution if you got this problem.
1. Go to Settings -> Wi-Fi
2. Tap and Hold on the name of your Connected Wi-Fi network.
3. Select Modify network
4. Scroll down a little and check ☑ Show advanced options
5. In the IP Settings - Select -> Static
6. Change DNS 1 - 18.104.22.168 and DNS 2 - 22.214.171.124 and Save and Voila !
And if you don't want to follow this steps then simply Factory Reset phone and it works like a charm.