Linkpack makes use of some iOS8 APIs (it has a Share Extension, it uses the UIVibrancyEffect and UISearchController etc) that would increase the development time if we decided to support older versions. I understand the frustration but this was a decision we had to make in order to speed up the development. Plus iOS8+9 now make up the 94% of the install base according to Apple: https://developer.apple.com/support/app-store/.