FabFilter

You can only use Pro-Q 3 presets in Pro-Q 4 if you are using the plug-ins' internal preset browser. In that case you will see them in a V3 folder in the preset list of Pro-Q 4, which will have all your Pro-Q 3 presets.

If you are using the preset browser of your host you will not be able to load Pro-Q 3 presets in Pro-Q 4, as the browser simply sees them as individual plug-ins. In that case you'll have to manually load a preset in Pro-Q 3, save it in preset browser of Pro-Q 3 and then load the preset in Pro-Q 4 from the v3 folder.

Hope that clears it up. If you have any more questions, just let us know!