If you are wondering why Apple released these new software updates for older iPhones and iPads, we have a great video from iDeveHelp which explains why these updates have been released
The reason the update has been released is to fix a bug in older devices that may affect GPS data, if you want to continue to have accurate GPS on your device then you need to install the update. The update will also ensure that you continue to have an accurate time and date on your device.
The updates have been released for a number of devices, this includes the Pad Mini, the iPad 2 and the iPad 3, plus iPhone 5 and also the cellular version of the iPad 4. You can install the updates by going to Settings > General > Software update on your device.
Source & Image Credit: iDeviceHelp