Windows 10 Build 10158 and up product keys
The Insider Preview build of Windows 10 are getting new products keys. If you are upgrading from a previous build you should not get any problem with the old activated keys. If you are doing a new clean install you will need to type in the right product keys. Clean install can be done when the ISO file is available later (when the build hits slow ring), or when you create your own ISO with this guide from the ESD file