If you are trying to update to iOS 7 Beta 3 and get the “Unable to check for updates” here is how to fix that little problem.
1.Go to SETTINGS
2. Go to Wifi
3. Open your current Wifi screen (which should be checkmarked)
4. Scroll down to the DNS
5. Record the numbers so that you can replace them after the download
6. Change the numbers to 18.104.22.168
7. Exit out of SETTINGS by hitting RETURN on the screen keyboard
8. HIT the HOME button
9. Go back into SETTINGS
10. Go into “General”
11. Choose SOFTWARE UPDATE and you SHOULD GET THE UPDATE!
12. After the update & verfication, the IPhone will reboot and finish installing
13. Finally, remember to go back into SETTINGS – WIFI – and replace the DNS numbers you originally started with.
Hope this helps, let us know below if it did!