PHost 4 introduces some slightly different file formats. Older PDK add-ons will not work with it until they are recompiled with a PDK that supports PHost 4. Once that is done, the add-ons will function equally well with PHost 3 and PHost 4. Add-ons that do not use the PDK must be ported, if they use auxdata.hst.

This is a testing version.
It may be incomplete, and have more bugs (or features) than the public live version at planetscentral.com.