Microsoft released a new beta version of Windows 10 for Windows Insiders in the fast ring today. The biggest change this time around: you'll be able to use your Windows 7, 8, or 8.1 product key to activate Windows 10 directly.
This change stems from the fact that some users couldn't activate Windows 10 online after upgrading. When this new build goes live, users will be able to enter their old product key in Windows 10 after installing. Users will also be able to enter their old product key directly during a boot media install of Windows 10. In Microsoft's own words:
If you install this build of the Windows 10 Insider Preview on a PC and it doesn’t automatically activate, you can enter the product key from Windows 7, Windows 8 or Windows 8.1 used to activate the prior Windows version on the same device to activate Windows 10 by going to Settings > Update & security > Activation and selecting Change Product Key. If you do a clean install of Windows 10 by booting off the media, you can also enter the product key from prior Windows versions on qualifying devices during setup. Refer to the Insider Hub for more information on these activation improvements including requirements.
Microsoft's blog post isn't entirely clear on one point, though—whether one still needs to actually upgrade to Windows 10 at least once before doing a clean install. The Insider Hub post doesn't actually have any more details, either. Despite the company's vague wording, it may well be possible for users to skip the in-place upgrade step.
As with any Insider build, there are lots of other small tweaks and changes. Improved Skype integration, colored window title bars (yay!), and minor tweaks to Edge and Cortana round out the list. Since this is a fast ring build, there are a number of potentially show-stopping bugs to be aware of, as well. Be sure to read Microsoft's full release notes before taking the plunge.