Free upgrade to Windows 10 RTM for all Insiders on July 29
All Windows Insiders will receive the final release build as a regular update
Microsoft announced upcoming changes to Windows 10 Insider builds. In a blog post, the company explains that the final Windows 10 RTM version will arrive to all Insiders via a normal Windows update.
Once upgraded to Windows 10 RTM, all Insiders will have a valid licensed copy of the OS. In other words, existing Windows 7, 8 or 8.1 licenses are not required to receive Windows 10 for free.
The blog post clarifies the update process:
“As long as you are running an Insider Preview build and connected with the MSA you used to register, you will receive the Windows 10 final release build and remain activated. Once you have successfully installed this build and activated, you will also be able to clean install on that PC from final media if you want to start over fresh.”
In order to upgrade to Windows 10 RTM on July 29 you need a Microsoft account synced to your PC. The same account should be previously registered as an Insider and an early Preview build must be installed on the machine.
The current preview build for PC is 10130. If you join the program now, install this build from an ISO file, link your account to the PC and then upgrade to Windows 10 final version on July 29, your OS will remain activated. You can even clean install from media to start fresh, after upgrading to the final build from earlier preview builds (10130 or newer).
At this point, it is not clear if users will be able to skip new Insider builds, coming after Windows 10 official version in July, without losing their free licenses.
Windows Insider program registration & downloads [link]