iOS Legacy Support, is it worthwhile?

I need to add a method to an app I am writing that only works on 开发者_开发百科iOS 4 (and above), there is a way I can do it that works on anything above iOS 2 but Apple says that the use of this older method is discouraged in iPhone OS 4.0 and later. My question is if I go with the newer iOS 4 method will I be severely limiting the user base of the app. I would assume that most folks have upgraded to iOS 4, but I really have no idea on the numbers involved. I am just curious as to what others think?

If there is a perfectly good function that works for iOS 3, I say use it, deprecated or not. Wait until you create an app that actually needs new functionality from iOS 4 before you shut out the older devices.

I don't know what the ratio of 3.0 devices to 4.0 devices is, but I wouldn't be surprised to find out there are still quite a few 3.0 devices out there. I always target 3.1, and I plan to continue to do so for at least another year.

Here's my 2c: I think most people will upgrade because it is so easy to do so I wouldn't bother caring about lower versions of iOS4 - but that just my opinion.

Agree with Anders K on the basis of opinon (hence +1) - however it may be useful to keep in mind that iOS4 on a 3g or 3gs iphone is really slow and I know many people who dislike iOS4 and I'm sure there are even more who won't want to upgrade because of the issues.

Plus if you want to transfer to iPad (the current version) it will be difficult if you use features only available in iOS4 and above.

All that said - I wouldn't bother, personally. Its easy enough for people to upgrade.