Apple has issued a software update for the latest iPhone to help fix connection problems that led to a flurry of online complaints from customers.

T-Mobile said the software was available for users to download to their iPhones on Tuesday, but that it was not yet clear if the upgrade would fix all the connection problems.

AT&T Inc the only U.S. network operator carrying the iPhone, confirmed that Apple had provided a software update but declined to give details about what it was aimed at fixing.

One of the key attractions of the latest iPhone is its faster, third-generation (3G) Web connections when compared with the first iPhone that was launched in mid-2007.

However, users around the world have complained about dropped calls and inconsistent Internet speeds, with the phone often reverting to a slower technology known as Edge even in 3G areas.

The iPhone 3G has gone on sale in about 22 countries since its launch on July 11.