Welcome to the Community Forum and thanks for your post. Apologies, but I'm not sure what the problem is and I'd like to help further if you are having connection issues on your phone after an upgrade.
Please let me know if you are able to make and receive calls and text messages and if your mobile data works on your phone.
If you are still having an issue with this, please send a private message to me so that I can look into this further for you.
Please provide the following details:
To PM me, simply:
Click on my forum name on the left of this post.
Go to my profile.
On the right had side, select the 'send me a message' option.