CUPERTINO, Calif. » Apple has released a software update to fix a problem that is shortening the battery life of some iPhones, iPads and iPods.

Apple has said that a small number of customers have reported lower-than-expected battery life on devices running on the company’s iOS 5 operating system. That’s the software that comes with the iPhone 4S and was available as a free upgrade for some older devices — both iPads, the iPhone 3GS and 4 and the two most recent models of the iPod Touch.

Apple released version 5.0.1 on Thursday to fix bugs it found with the software. Users can get the update by connecting to iTunes.

Other changes in the update include better voice recognition for Australians using dictation.

Some users who upgraded the software said they still had issues with battery life. Apple said Friday that while the update addressed many of the problems, "we continue to investigate a few remaining issues."