The iOS 4.1 update has been released to developers signed up with Apple's iPhone developer programme, according to various sources.
Early reports point to few apparent changes, save for a slight difference in the way the signal reception strength bars are displayed.
This makes it likely that iOS 4.1 is the free software update promised by Apple earlier this month in response to the signal strength issues users have experienced.
However, those who have already downloaded the update report that it does not fix the problem of poor signal reception when the iPhone is held in a certain way.
As reported earlier, Apple discovered that a flawed algorithm in its software meant that the iPhone was indicating stronger network reception than was actually the case.
While the iOS 4.1 update thus appears to correct the signal strength indicator, it is unlikely to help users experiencing a fall-off in bandwidth or dropped voice calls.
The actual design of the new iPhone has been blamed by many for this problem, specifically the incorporation of its wireless antenna into a steel band that girdles the handset.
Speculation is now mounting that Apple may be forced to recall all iPhone 4 handsets in order to deliver a fix for the problem.
A press conference scheduled for Friday at the company's headquarters in California is expected to shed more light on the subject.