Since Apple launched the new iPhone 4S two weeks ago, some users have complained online that the battery drains much more quickly than is normal, often lasting less than half a day.
It seems that the problem is not confined to iPhone 4S users, with some users of the iPhone 4 also noticing poorer battery performance since they upgraded to iOS 5, the latest version of the operating system that runs Apple's iPhone, iPad and iPod touch.
Oliver Haslam, of iDownloadblog, has suggested that the problem is related to the location settings of the iPhone. He says that a bug in iOS 5 has caused the device to continually check the time zone it is in.
He writes: "Switching it off may mean that your iPhone will no longer set its own time zone when you travel, but that’s a small price to pay for having your iPhone last more than 12 hours on a full charge."
Some users report that Haslam's suggestion but others say they have not seen an improvement.
It's not clear how many people are affected. More than 2,000 people have commented on the battery life thread on Apple's support website, though not all of those are claiming to have the problem.
The iPhone 4S that I've been using for the last three weeks has no battery life problems at all.
Apple declined to comment.