What made the twitter app work on only 27% of phones? I Doubt is the display resolution or the buttons configuration. Must be simply the OS version. In that cas

What made the twitter app work on only 27% of phones? I Doubt is the display resolution or the buttons configuration. Must be simply the OS version. In that case, it's quite a universal problem, one that apple is going to have too now that people have to deal with two OS versions and at least 4 devices (iphone 3g, iphone 4g, ipad, itouch). A wise developer would just code something that would work on any version above 1.6 If I were making mobile apps, I'd probably make an iphone version and an android version.