Back in 2013, Apple announced that its iPhone 5S was the first smartphone to support 64-bit applications. This was coming with Apple's A7 chip, though apps needed to be updated to work on the 64-bit architecture. App developers at the time either updated their apps or left them as-is. Afterwards, in order for new apps to become available on the App Store, 64-bit code was a requirement once February 2015 came around. This means that some of the older apps in the App Store portfolio may not be 64-bit, and are running in 32-bit emulation. RIP 32-bit emulation mode in iOS 11?...
Source: http://www.gsmarena.com/apple_may_no_longer_support_32bit_apps_in_ios_11-news-23105.php
