Windows 10 build 10240 released for Windows Insiders in both Fast and Slow rings

[WindowsCentral.com]

Microsoft has released a new version of Windows 10, build 10240, that will be available for Windows Insider members on both the Fast and Slow update rings. This is the build that is rumored to be the RTM (Release to Manufacturing) version that will be sent to PC OEMs.
Windows Insider head Gabriel Aul wrote:

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[slyronit]

The question now is, for the devices that are still on 8.1, what is the difference between getting 10240 now, opting out of insiders and waiting till July 29 (or beyond)?

Will upgrading from a valid 8.1 licensed device count as a license upgrade to Windows 10, or would I need to go back to 8.1 and get the update without insiders?