Apple has removed many restrictions in its developer agreement and published guidelines about the apps it will accept and reject.
The planned restrictions were met by complaints from developers, but in an apparent about-turn, Apple has announced changes to its iOS Developer Program licence terms.
The new agreement allows developers to use almost any programming tool, including Adobe Flash Packager for iPhone, according to US reports.
This will not bring the Flash platform to the iPhone, but apps created in Flash and translated using Adobe's Flash Packager for iPhone can now be judged on their merits rather than their technology.
Earlier this year, Apple chief executive Steve Jobs said he would not allow Adobe Flash software on mobile devices such as the iPhone, because of security flaws.
Announcing the new agreement, Apple said: "We have listened to our developers and taken much of their feedback to heart."
Apple said it will relax some of the restrictions put in place earlier this year, including all restrictions on the development tools used to create iOS apps.
But, the company said the resulting applications must not download any code.
"This should give developers the flexibility they want, while preserving the security we need," Apple said.
The company also announced that it would publish the App Store Review Guidelines for the first time to help developers understand how Apple reviews submitted apps.
"We hope it will make us more transparent and help our developers create even more successful apps for the App Store," the company said.