This sounds like the upgrade has corrupted or deleted your Mobile Network Settings.
These are found in Settings - Mobile Network - Access Point Names.
In there, there should be at least one set of settings with a highlighted dot next to the name for the settings. If you open the settings, all the information that is in there is needed for the phone to connect to your carriers mobile data network.
To check it is correct or to input the missing settings, you have three options:
- If you let us know who your carrier is, then someone on that carrier can let you have the correct settings
- You could contact your carrier, for them to give or send you (by SMS) the correct settings
- Use Google to find a list of the correct settings for your carrier
See if that helps