New version of Apple’s software appears to slow down the iPhone 4S, 5 and 5S in side-by-side tests, although disabling features may speed things up

Users complaining that their iPhones have slowed down after updating to the latest iOS 9 software may not be imagining it.

The new iOS 9 operating system works on models from 2011’s iPhone 4s onwards, with the company claiming that more than 50% of iOS users had already installed the update within a week of its release.