"Update to iOS 10.3.4 before November 3, 2019 to continue using App Store, iCloud, email, web, and other services," Apple warned iPhone 5 users through a notification delivered to their devices.
"If the update to iPhone 5 is not completed by November 3, 2019, you will be required to back up and restore using a Mac or PC in order to update because over-the-air software updates and iCloud Backup will not work."
Apple explained on its website that the reason for this involves a GPS time rollover issue that began affecting GPS-enabled products from other manufacturers in April.
"Affected Apple devices are not impacted until just before 12:00 am UTC on November 3, 2019," said the company.
New iOS update for older devices
Alongside its recent launch of iOS 13.2, Apple also opened up the new iOS 12.4.3 update to users of older Apple devices.
iOS 12.4.3 offers various security updates, and Apple recommends that all users of supported devices download the update.
The devices are:
iPhone 5S
iPhone 6
iPad Air
iPad Mini 2
iPad Mini 3
iPod Touch 6th-generation
Models older than these devices, including the iPhone 5, are not able to update to iOS 12.4.3.