Apple stopped releasing updates for the iPhone 5S in 2018 with the launch of iOS 12, but if you still own this phone, you have one more version of the software to download.
How does the AppleInsider website, the company released the iOS 12.5.7 version for this mobile phone originally released in 2013. The update serves to correct a vulnerability in the operating system present in the iPhone 5S, which may have been “actively exploited” by third parties.
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Note that, in addition to the iPhone 5S, the iPhone 6 and the iPhone 6 Plus are also eligible for this update and it is recommended that, if I have one of them, I also update.