Owners of older iPhones and iPads must perform a crucial update by Sunday, or they could be stuck with an inoperable device.
Apple alerted owners about the upgrade this week. It affects people using an iPhone 5 or a fourth-generation iPad (WiFi and cellular) running iOS 10.3.4 or an iPhone 4S, a third-generation iPad (WiFi and cellular), a second-generation iPad (WiFi and cellular, CDMA only) or a first-generation iPad Mini (WiFi and cellular) running iOS 9.3.6.
The update is needed, according to radio station KJCE, "to maintain accurate GPS location and to continue to use functions that rely on correct date and time including App Store, iCloud, email and web browsing."
A "GPS time rollover issue" that first was discovered in April is what's behind all of this.
Without the update, the iPhone 5 will essentially become useless, with email and many apps becoming inaccessible. The impact won't be quite as bad on the other Apple products, with only GPS capabilities being affected.
The iPhone 5 was last made in 2013.