If your faithful iPhone 5 is still your go-to device, you must update its software by Nov. 3.
At midnight UTC on Nov. 3, older iPhones must be updated to 10.3.4, according to Apple.
Also, by updating, your device will have accurate GPS location and the correct date and time for the App Store, the iCloud, email and browsing the web, according to Apple.
If they are not, then updates will have to be done via backup and restore using a Mac or PC.
For more information, click here.