iPhone 4S
Developer Zachary Drye has provided an easy method of enhancing the speed of older iPhones on his Twitter accountRobert Galbraith/Reuters

Those using older iPhones will be thrilled to know that they can enhance the speed of their devices with a few easy steps disclosed by a developer from San Francisco. Zachary Dryer, on his Twitter account, said that iPhone users need to navigate to the App Store and then tap any of the five buttons displayed at the bottom of the screen 10 times in succession.

Once this is completed, the screen will blink and go white for a few seconds and then will reboot and land on the App Store's homepage, indicating that the phone's cached memory has been cleared.

Cached memory is data held temporarily on a device. But when a lot of data is accumulated or due to software errors they can remain on a device for extended periods of time, taking up extra space and slowing performance. Users can also apply the same trick to clear cached memory in iPads. The trick also works on iTunes and iBooks.

Apple iPhone users have often complained that their older handsets – such as the iPhone 4s – lag in performance after upgrading to the latest iOS 9 operating system. In December 2015, around 100 iPhone 4s users came together to sue Apple for $5m (£3.3m) blaming the company for sluggish performance of their device after installing iOS 9.

They claimed that the company knew that the operating system of iPhone 4s, if upgraded to iOS 9, would make the device sluggish. They also said that apps were not launching fast enough and the device's touch screen was not functioning as efficiently as it was prior to installing iOS9.