Based on the official information, the software is not ready for WIndows 10, nor is there any information related to this. I have searched without results. The best way to obtain an official statement is through the contact reference. There is a contact and a live section where you can get in touch with Tech Support. They will explain you what needs to be done until Windows 10 update comes for the GPS or software.
Contact page: http://www.randmcnally.com/about/contact_us