Starting with PSPDFKit 4, we no longer include an armv7s binary slice.
Apple no longer requires or encourages armv7s - this is the new default since Xcode 6.
It only slightly improves performance on iPhone 5/5c and only if it's a floating point heavy application; but would increase download size and makes compilation times longer.
The reason for including armv7s would be marginal backward compatibility. But the general differences between armv7 and armv7s instruction sets are minor. So if you choose not to include armv7s, the targeted armv7 machine code still runs fine on 32 bit A6 devices, and hardly one will notice performance gap.