Microsoft has released Windows 10 Insider Preview Build 10525.
Here is how you will get it:
If you’re already a Windows Insider and have been running Windows 10 Insider Preview builds – there is nothing you need to do. You will automatically be upgraded or you can upgrade your build via Windows Update. If you want to get a Windows 10 Insider Preview build installed on a PC running Windows 7 or Windows 8.1, you should first upgrade to Windows 10 using the free upgrade offer* available to qualified, genuine Windows 7 and 8.1 devices. From there, you can opt in to the Windows Insider Program via Settings app > Update & Security > Advanced options under “Get Insider builds”.
Windows 10 Insider Preview is intended to be installed on genuine Windows 10 devices – before upgrading to Windows 10 Insider Preview Builds or reinstalling Windows 10 please ensure your device is activated. To confirm go to Settings > Update & security > Activation. With the launch of Windows 10 we introduced device based activation. If you’ve previously activated a genuine copy of Windows 10 on your device, you’ll be able to activate Windows 10 Insider Preview builds of the same edition without the need to enter a product key. This will also enable you to re-install the latest public release of Windows 10 without entering a product key if you no longer want Windows Insider Preview on your device.
More information Here