Apple's new iOS 7 operating system has become the fastest software upgrade in history, according to the industry giant.
More than 200 million devices are now running on the new system, which was launched just two days before the new iPhones went on sale.
Apple has also announced a record-breaking nine million sales of the new iPhone 5S - which features a fingerprint security scanner - and iPhone 5C models three days after going on sale.
As the new phones went on sale, hundreds of people took to Twitter to say that shops had run out, while Apple’s online store pushed back its dispatch date for new phones to October.
Around 1,500 were in the queue outside the door of the Apple flagship store in London on Friday at 8am when the devices went on sale.
In the US, homeless people were hired to queue overnight outside a store in Pasadena, California, to be first in line when the doors opened.
But the plan backfired when several of them were arrested for fighting.
Apple CEO Tim Cook said: "This is our best iPhone launch yet - more than nine million new iPhones sold - a new record for first weekend sales.
"The demand for the new iPhones has been incredible, and while we've sold out of our initial supply of iPhone 5s, stores continue to receive new iPhone shipments regularly. We appreciate everyone's patience and are working hard to build enough new iPhones for everyone."
Despite the speed of the iOS 7 upgrade, Apple's new-look operating system got off to a rocky start, with users complaining of having difficulties.
Many people complained about long download times, while others had to go through multiple attempts to install the software.
One typical error message read: "Software Update Failed: An error occurred whilst downloading iOS 7.0."
Meanwhile, many other users have reported worse battery performance with the new system.
Apple billed iOS 7 as the most significant iOS update since the original iPhone.