What will happen if you run Flash application which uses class, method, or property which is not supported by your Flash Player?

Question

For example, if an application uses class, method, or property which is supported only by Flash Player10.
(I also want to know what class, method, or property is supported only by Flash Player10.)

When you run the application on Flash Player9, what will happen?
Flash Player will be crashed?
Or Flash Player will show you a message screen to upgrade your Flash Player?
Or the application will normally run and will ignore the part which uses the unsupported class, method, or property?
Or the application will cause a runtime error when the unsupported class, method, or property are called?

Answer 1

Sad truth, if you try to run swf built for FP10 in FP9 your swf will freeze in the end of the loading and won't show any notification, error message, popup with upgrade, etc.

If you try to run swf which uses some features of FP10.2 in FP10.1 you'll get runtime error, saying the used class could not be found.

Here there is the list of new features of FP10:

• Flash Player 10 features
• Flash Player 10.1 features
• Flash Player 10.2 features
• Flash Player 10.3 features

Answer 2

When you compile a project, you have to choose the target player version (in the Publish settings for Flash CS), so that informs the Flash player what version is required. Then when you run this SWF file in a Flash player, it's going to check the SWF's version number. If it's greater that the player's number, you'll have a popup asking you to upgrade your player.

As for the list of Flash 10 features, I don't know any list but the classes that pop to mind are all the 3D stuff (Matrix3D, Vector3D, PerspectiveProjection, GraphicsTrianglePath), the Vector class, and some of FileReference's methods.