New updates of CMFC will only support iOS 6.1 or above

Until now, CMFC (Crossword Maker For Cruciverbalists) supports almost every iOS devices, including the 1st gen iPad, as long as they are using iOS 5.0 or above. But the upcoming upgrade (version 5.1.0) will drop the iOS 5 support, and will not be downloadable on an original iPad.

It’s a difficult, but inevitable decision. Although the new Xcode 5 still supports submitting an app which supports iOS 4.3 or above, it does not have the iOS 5 simulator any more, and could not execute / debug the app on an iOS 5 device (i.e. my iPad 1). There are a few major improvements with the new update. Technically it’s impossible to test all the features to make sure they are still working correctly with iOS 5. So it seems the only choice is dropping the iOS 5 support, and concentrating on newer devices which supports iOS 6.1 or iOS 7 (including every iPad later than iPad 2, and every iPhone later than iPhone 3GS).

And as Apple has offered the “downloading last compatible version from App Store” feature since a few weeks ago, people who still have the original iPad may still download the CMFC 5.0.0 when newer devices keeping the free upgrade for the recent versions.

I feed sad that the original iPad may not enjoy the new updates of CMFC any more. However, I also feel relieved when thinking about the brightness side of dropping the support to iOS 5. The newer iOS SDK have some powerful features I could not used before. And it’s now possible to make a maximum use of them in new CMFC updates, and serve our users better.


Fragment Shader Performance Comparison: iPhone 5 vs iPhone 4

No surprise. With a simple raytracing shader (i.e. not-optimized, with massive dynamic branching and arithmetic operations), iPhone 5 easily achieved 26.5 fps, while iPhone 4 could only have 2.2 fps.

The test scene was simple. There was a red sphere, and a green triangle in front of it. A point of light was rotating around the sphere, lighting both objects, and cast shadow on the sphere.

iPhone 5’s PowerVR SGX543MP3 GPU is truly a performance monster among the family of mobile devices. It would have the potential to perform some of the effects which was only available to desktop PC or video game consoles.


Build A Fully Functional, Robust and Secure Passbook Server with (Almost) Zero Cost


This post discussed the implementation of a fully workable Passbook server. Instead of a step by step tutorial, it mentioned some technical decisions and considerations in a realistic Passbook server implementation.

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