I'm disappointed to hear you're having issues with the signal on your iPhone.
There's nothing in the update that should have affected the signal levels you're seeing, so can I ask if you get this issue everywhere or just at these two locations?
If you get good signal at other locations, it may be that there is something which is affecting the local signal strength. If you can check the network troubleshooting thread for us and follow the steps in there, then post back the information, we'll be able to get a better idea of what is happening.
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