Microsoft may be planning to take care of complaints of not able to enable “Static IP” in Windows Phone. The Windows Phone 8.1 GDR1 documentation talks about “Enable Static IP” option. OEM partners can enable to show the static IP settings under Settings > Wi-Fi > advanced. Currently when you navigate to Settings > Wi-Fi , you don’t see an advanced option.
Flash a build containing this customization to a phone connected to Wi-Fi.
Go to the Settings > Wi-Fi screen and tap advanced.
Verify that you can see the advanced static IP settings.