Apple released a warning note to all the older devices and call on immediate action. The older device here means the iPhone 5, iPhone 4 and the earlier models. Apple suggests the users of these devices go in their setting and update the software to the latest available version before November 3. For some of these devices that will be iOS 9.3.6, for other iOS 10.3.4, depending on their age.
What’s the exact issue with these older iPhone models? Any device that is not updated before the 3 November deadline can expect GPS location issues as well as potential problems with keeping accurate date and time. The latter in turn could prevent Apple gadgets from fetching further updates over the air and sync with certain online services like iCloud and email servers. Post 3 November, a tethered update via iTunes will be required to bring them back to normal operation.
If you think that the issue prevails only on the Apple devices than wait the issue is much bigger than Apple’s own domain and could actually affect pretty much any GPS-enabled device that has not bee properly patched or prepared at some point to handle what is essentially a GPS Y2K event.
If you want to go in the deep of how the GPS system works and to understand what is troubling the devices to cop up accurately with GPS then you can read furthermore here in this article.
Again, we realize this might be a scary analogy to make, but it is a pretty accurate one. The short of it is that GPS systems in general count weeks using a ten-bit variable or register. Hence, values can only go from 0 to 1023 on the said counter. When a device hits week 1024, if not programmed correctly, it could restart or “rollover” said counter in a way that corrupts it and makes it no longer usable for working with GPS and its precise timing data.
Absolutely precise time keeping is crucial for GPS operation. So, why is this happening now? Well, the first GPS week counter was kicked off on January 6 1980. Then, on August 21 1999 the week counter got full for the first time and needed to be restarted. That was the end of the first “GPS epoch”. Counting forward, that puts the end of the second epoch on April 6 2019.
Some manufacturers and software developers might have restarted their GPS week counters at a later time. The GPS firmware was compiled and shipped to devices. Apparently, this was the case for Apple and that’s where their precise calculation and the November 3 deadline come from.