Apple is set to cut adrift application developers who don’t write iPhone applications to support their upcoming iPhone OS 3.0.

Beginning today, any app submitted for the iPhone App Store must be compatible with the latest beta, version 5, of the iPhone’s software, the company said.

“We sent an e-mail to developers yesterday saying all submissions to the App Store will be reviewed on the latest beta of iPhone OS 3.0 in preparation for the millions of iPhone and iPod Touch customers move to iPhone OS 3.0 this summer,” an Apple spokesperson told InternetNews.com

According to the e-mail sent to developers, “If your app submission is not compatible with iPhone OS 3.0, it will not be approved.”

While Apple said that existing apps in the App Store should already run on iPhone OS 3.0 without modification, it also urged developers to “test your existing apps with iPhone OS 3.0 to ensure there are no compatibility issues.