What is the three version back product upgrade policy?
Adobe allows upgrades to the current version of Creative Suite products and components from three versions back. For example, if you have a validly licensed copy of Photoshop CS2, CS3, or CS4, you can upgrade to Photoshop CS5. You are not eligible for upgrade pricing if you are a Photoshop CS or earlier customer. The exception to this rule is Adobe Premiere Pro and Adobe Premiere, which allow upgrades to Adobe Premiere Pro CS5 from any validly licensed earlier version. Prices vary depending on which version you are upgrading from (see next question). If you do own a version older than three versions back of any product other than Adobe Premiere or Adobe Premiere Pro, then you will need to purchase at the full retail price.