A comment by Ed Oswald on the Windows Phone OS and increased fragmentation:
Microsoft has chosen Android’s fragmented path against any good sense. While I understand this likely has to do with the drastic code changes under the hood, it still does not make sense why older legacy devices cannot be factored into the equation. Windows Phone developers must now contend with the fact that a sizable portion of the market will never be able to upgrade. Apps written for the lowest common denominator win again.
It isn’t nearly as bad as Android, but the recent decisions regarding the Apollo release are disheartening for both developers and users. There is some relief in knowing that display resolution is something that Microsoft is taking seriously. The problem is that they create lack-luster devices like the 900 that show awful scaling with resolution as an emphasis.