Apple has, following a wave of criticism from its 1.7 million customers, released an update for its new iPhone operating system: iOS 4.0.1. 

The update, which comes just days after the new OS has been made available, aims to fix the widely reported problem of reception issues created by the new iPhone 4 design. 

It's now available via iTunes, and brings the promise of improved monitoring of reception for the OS.

It "improves the formula to determine how many bars of signal strength to display", says Apple in the support notes.

The update is compatible with the iPhone 3G, iPhone 3GS, and, of course, the iPhone 4.

Check out the latest on the iPhone and iOS 4, plus read our Apple iPhone 4 review to see what we think of the latest handset from Apple.

Users will be prompted to update to the new OS version when connecting their iPhone.

The news comes just hours before Apple's press conference for the iPhone 4, in which the company is expected to detail how they plan to fix problems some people have been having.

Earlier on Thursday Apple released iOS 4.1 to developers.

Let us know how you get on once you've downloaded it.