Hello,
Usually, install over should be fine, but it is best to uninstall old and install new. But, I am not sure if Multiplicity 3 setting will be correctly carry over to Multiplicity 4. To be sure, I have forwarded your question to Stardock Support Team for their assistance. Please keep an eye on this thread for any updates. We appreciate your feedback and patience.
Note: Stardock is starting on its Summer vacation, so, respond might be slow.
Thank you,
Basj,
Stardock Community Assistant.