Keeping your iOS device up to date is pretty important.
Apple introduce all sorts of security and performance updates as well as new features with almost every release.
To stay up to date, do one of the following three methods – in all cases make sure you do a full sync beforehand.
1. Automatically – when you plug your iPhone, iPad or iPod Touch into your PC or Mac and launch iTunes you may be prompted by iTunes to update if one is available. Simply click download and install.
2. Manually – after plugging in your iOS device and opening iTunes select your device from the left hand navigator under ‘Devices’ and then click the ‘Check for Updates’ button
3. Even More Manually – you can download the actual iOS software and then update your iPhone by uploading it onto the device via iTunes.
[...] You can learn the various ways of updating your iOS device’s software in this tip. [...]