DxO is using a very confusing naming system, Connie. When you go to their website or load one of their products, the latest Nik Collection version is 3.3. Within that suite, some of the apps display no version number (implying version 1), some dislay that they are version 2, some display that they are version 3 and some display that they are version 4. Yet when you view the properties of each corresponding .exe file, the version number is 5.0.3.x. That's at least how everything is displayed on my PC system using the Nik Collection as a Photoshop plug-in. DxO could surely make this more confusing, but they would have to try very hard to make that happen.