While Apple had released the iOS 4.1 update to developers, now they have released the iOS 4.0.1 update for iPhones and iOS 3.2.1 for iPads. What’s new for the iPhone is that they have changed the bar sizes which is the supposed fix for the iPhone 4 reception problems.
Anandtech has done an analysis on the signal bars vs signal strength. The update not only changes the size of the bars but also increases the range of each bar which seems to be distributed more evenly. This seems to represent more accurate reading as 1st-4th bars are previously mapped pretty close to each other.
Numbers and display aside, that still doesn’t solve problems of alleged drop calls and interference when using the device. It is too early for us to say but maybe there’s something extra on the software update that we might not know which could possibly improve call reliability.