As to why the iOS 10.3.4 update is important for the iPhone 5, it’s because the update addresses the GPS time rollover issue. For context, GPS-enabled devices measure time and date in denominations of weeks. In the case of the iPhone 5, the phone is only able to count up to 1024 weeks. After which the counter resets back to zero.
As GPS requires accurate time data to work precisely, the reset could disrupt the feature, causing it to display inaccurate data. This issue is similar to the Y2K Millenium Bug, where programs back in 1999 would suffer a malfunction when the computer’s internal clock date strikes 1/1/2000. According to ArsTechica, newer devices are not affected as it has been made to adapt to the rollover issue. Currently, Apple says that the iPhone 4S, 1st generation iPad mini, iPad 2, and 3rd and 4th generation iPads are affected. However, the Wi-Fi-only models are not affected.
You can download iOS 10.3.4 on your iPhone 5 via the Software Update page for an OTA update, or via your PC. As mentioned, the rollover will occur at 8am Malaysian time on 3 November 2019. (Source: Apple, Ars Techica via The Verge // Image: Apple)
