UPDATE: September 2016 - A Knight’s Move for iOS is no longer available.
A Knight’s Move for Mac is still supported.

A Knight’s Move for iOS has been updated to take advantage of the taller iPhone 5 screen.

In-app purchasing of packs has been removed from both Mac & iOS versions.
For iOS, the app is now free but supported by iAds (please click through if you would like to show your support).
Apple does not have an ad system for Mac, so the Mac version is now a paid app that includes all the puzzle packs.

The in-app purchasing was an interesting experiment, but the ratio of purchases to downloads was too low to sustain the development.