Apple has announced that developers of applications for the iPhone no longer need to sign the non-disclosure agreement (NDA) that previously accompanied its software developer kit.

The NDA caused a lot of bad feeling in the developer community for being far too restrictive.

Developers were not allowed to discuss the contents of the SDK, for example, nor the reasons for any application being refused by the iPhone App Store.

"We have decided to drop the NDA for released iPhone software," said the company in a statement.

"We put the NDA in place because the iPhone operating system includes many Apple inventions and innovations that we would like to protect, so that others do not steal our work. It has happened before."

Apple has now acknowledged that the NDA "created too much of a burden on developers, authors and others interested in helping further the iPhone's success" and is dropping it for released software.

"Developers will receive a new agreement without an NDA covering released software within a week or so," the statement confirmed.

Developers had complained that the terms of the NDA stopped them from discussing common problems and producing less buggy code. Some also felt that Apple was too enthusiastic in banning certain applications that competed with its own software.