iZotope plug-in presets are compatible 1 version across, so you can open Ozone 8 presets in Ozone 9 and Neutron 2 presets in Neutron 3 etc.
The best way to transfer those is to save a preset in the Preset Manager of that plug-in, which will appear as a .xml file here:
Mac HD > Users > [Username] > Documents > iZotope > [Product Name] > Presets
C: > Users > [Username] > Documents > iZotope > [Product Name] > Presets
You can simply drag and drop / copy and paste that file to the same location with the newer version.
Converting Ozone 8 global presets to Ozone 9 on a mac would entail moving the desired .xml files from:
— Mac HD > Users > [Username] > Documents > iZotope > Ozone 8 > Presets > Global Presets
— Mac HD > Users > [Username] > Documents > iZotope > Ozone 9 > Presets > Global Presets
If you need to move a preset across multiple versions, for example, from Ozone 5 to Ozone 9, you will need to install all versions in between and re-export the preset. Feel free to reach out to Customer Care if you need help with this!
Currently, you cannot import Stutter Edit 1 presets into Stutter Edit 2 or Nectar 2 presets into Nectar 3.