I recently upgraded from a 4 to 4s (don't ask why I did this right before the release of the 5) and have noticed a substantial increase in the amount of dropped calls. This has been particularly at work, where call quality has never been great, but has since declined even more with the upgrade to the 4s. I thought this issue was handled back when the 4 experienced the same issue? It should also be noted that with the 4s, I am no longer using a case so maybe that has an effect on call connection. Has anyone else experienced a similar issue or found a way to resolve it?