New actionscript actions and variables and expressions. Better integration of Macromedia Products. Macromedia Flash 4 is the standard version. If an agency wants to use Macromedia Flash 5, have them clearly explain to you why it is essential they use v.5. If a presentation is saved as Flash 5, a user would need to upgrade the Flash plug in in his browser.
Many users shy away from upgrading.
You may gain in features, but you may lose viewers and users along the way. A good agency will know how to offer good quality presentations while still using Flash 4. Provide compatible GIF files to Flash graphics. For smaller Flash presentations or graphics it is necessary to provide a corresponding image or animated GIF to service users who don't have a Flash plug in. For large presentations and brochures, either an alternate GIF animation is needed or an alternate technique for viewing.