Vodafone has warned it's UK customers with the iPhone 4S not to upgrade to iOS 6.1.
Texts were sent out to iPhone 4S handsets on the network yesterday evening.
According to the company Apple's 6.1 update causes problems making calls, sending texts and accessing the internet.
Vodafone claims Apple is working on a solution and that the connection problems are intermittent.
A post on Vodafone's website states: "We're aware of an issue caused by Apple iPhone 4s handsets that have been upgraded to iOS 6.1 which impacts performance on 3G."
"Some customers may occasionally experience difficulty in connecting to the network to make or receive calls or texts or to connect to the Internet. Apple is working on a solution to their software issue. These connection problems are intermittent."
"While Apple's investigations continue, we would recommend that anyone who has not yet installed iOS 6.1 on their iPhone 4s should delay doing so until Apple has confirmed that their problem has been fixed."
As far as we are aware there are no problems with the other mobile networks in the UK.
The iOS 6.1 update introduced a few minor - but welcome - changes to the software including the reinstatement of iTunes Match features, a Reset Advertising Identifier and more LTE coverage.