As a reminder, iOS 7 will be compatible with the iPhone since the iPhone 4 , iPad for iPad 2 and iPod Touch from the fifth generation .
iOS 7 bringing many changes, Craig Hockenberry, developer of Twitterrific ( available here on the App Store ) has started working on the adaptation of its iOS app with 7 and was just asked the question of backward compatibility iOS 6, which could be very complicated and require a lot of time.
To get a better idea, he decided to run a poll first technical question was asked in order to properly get answers from developers.
In the end, 545 people are responding and if it appears that 95% of developers working on the adaptation of their iOS app with 7 , 52% (284 people) abandon compatibility with iOS 6 .

iOS7-dev

Of course, with a panel of 545 people, these results do not reflect a general trend but nevertheless gives an interesting indication.
For free applications, nothing prevents a developer to keep an old iOS 6 compatible version on the App Store and to develop an app exclusively for iOS 7.
But this choice could be very difficult for many developers whose application is not free, leaving paying customers on the floor and could limit the number of new customers, both compatibility by negative user reviews on the App Store that would feel cheated.
Remains to be seen for each developer what is the number of stuck with iOS 6 (iPhone 3GS or iPod Touch 4th generation) to see what strategy to users. For the first generation iPad, the problem is different because it had not been entitled to iOS 6.

Friends developers, have you ever thought about this compatibility? What will you do?