What Flash player version is required by Flex 3 app ?
Requirement seems to be HTML WRAPPER/ACTIONSCRIPT compiler setting inside FLEX development environment; what can I choose there to allow maximum compatibility with old flash players? Will v8 player work?
Flex is built upon ActionScript 3, and that was introduced in flash player 9 so V8 player would not work if you want to run flex 3 app on it.
To run ActionScript 3 you need AVM 2 (Actionscript virtual machine), flash player v8 cotains AVM 1 only. While flash player 9 contains both AVM 1 & AVM 2 for maintaining backword compatibility. So you would need atleast flash player 9 if u want to run flex 3 apps. V9 or V10 will give you all backward compatibility to ur existing flash applications