Ok guys, so some of you are getting the message that your 3G or 4G service is not working after upgrading to iOS9.
Go into your cellular data/mobile data settings.
Underneath the APN your username and password are blank.
Go into each one and put something in like “web”. Click back to save and go back in
Remove whatever you put in the username and password, so they are blank again.
Come out of settings and all should be well again.
I will update this post soon with images but it’s late and I need some sleep.