Iphone app compatibility question

I have an app used iphone4's new feature (MFMessageComposeViewController). b开发者_C百科ecause this class does not exist in iphone3, I have to use a workaround method (old code) to do the thing.

if ([self isVersion4]){ use new code } else { use old code }

I compiled my app in iphone4 SDK and it runs well. I want to know if the app cound run well in iphone3.

You've got to test it on iOS 3.x. Unfortunately, last time I looked, there was no way around this.