Adobe shares soared on Thursday after Apple appeared to open the door for programs converted from Adobe's popular Flash video software to run on the iPhone and other Apple devices.
Adobe shares were up 11.57 percent in early trading on Wall Street at 32.70 dollars.
Apple has banned the use of Flash on the iPhone, iPod Touch and iPad. Thursday's revision of the rules for programs submitted to Apple's App Store still does not permit the use of Flash on the devices.
But the new licensing rules would allow developers to write programs in Flash and then convert them into the iOS format acceptable to Apple.
"While the new changes by Apple still do not allow full Flash applications to run on the iPhone or iPad, this is a big positive for Adobe and its Flash technology," the International Strategy and Investment Group Inc said.
"While this announcement still does not allow for Flash to run natively, it nonetheless gives developers options," it said in a note to investors. "Flash still has the widest reach and is the most mature product for streaming video and rich Internet applications."
In its announcement, Apple said "we are continually trying to make the App Store even better. We have listened to our developers and taken much of their feedback to heart.
"In particular, we are relaxing all restrictions on the development tools used to create iOS apps, as long as the resulting apps do not download any code," Apple said. "This should give developers the flexibility they want, while preserving the security we need."
Apple on Thursday also published for the first time the guidelines it uses to approve or reject applications submitted to the App Store.
"We hope it will make us more transparent and help our developers create even more successful apps for the App Store," Apple said.
Instead of Flash, Apple devices support video built using HTML5, a fledgling software format created by a group of technology firms including Google and Apple.
Explore further: Samsung removes logo on smartphones in Japan