Straightforward Message from Apple

Apple is releasing iPhone OS 3.0 this summer and as such they made sure that all applications that are offered in their app store is 3.0 only compliant. As per their email to their developers —

All apps must be compatible with iPhone OS 3.0
Millions of iPhone and iPod touch customers will move to iPhone OS 3.0 this summer. Beginning today, all submissions to the App Store will be reviewed on the latest beta of iPhone OS 3.0. If your app submission is not compatible with iPhone OS 3.0, it will not be approved.

Existing apps in the App Store should already run on iPhone OS 3.0 without modification, but you should test your existing apps with iPhone OS 3.0 to ensure there are no compatibility issues. After iPhone OS 3.0

That was a straightforward message from Apple that forces developers to make their applications work on iPhone OS 3.0. I remember when Windows Vista first came out, it was incompatible with a lot of vendors and the software giant was blamed for this despite repeated reminder from vendors about the things they should do to make their applications work. Unlike Apple, Microsoft did not have a single repository of applications that would force vendors to fix their codes otherwise, it would not be sold to the store.