"The definition and evolution of Flex has been influenced by our incredibly talented developer community from day one," said David Mendels, senior vice president of Adobe's enterprise and developer business unit. "The decision to open source Flex was a completely natural next step. I am incredibly excited to deeply collaborate with the developer community on Flex, and further fuel its momentum and innovation."

Some observers suggest that part of Adobe's motivation for the change is Microsoft's forthcoming Silverlight (formerly Windows Presentation Foundation/Everywhere), but Adobe does have a track record in open source, including its contribution of the ActionScript virtual machine to the Mozilla Foundation.

Adobe has chosen to use the Mozilla Public Licence (MPL) for Flex.

The process of open sourcing will begin this northern summer with daily pre-release builds of "Moxie," the code-name of the next version, but it won't be until the Moxie's final release ("currently scheduled for the second half of 2007") that the MPL terms will kick in, allowing outside programmers to contribute to the project.{moscomment}