The WIN10 Technology Preview has been released for several months now, several major updates have also allowed Microsoft to fix a number of bug problems, and the technology Preview is about to complete its mission, and Microsoft will be releasing a public version of the consumer Win10 preview in January, while the WIN10 consumer preview version is simpler to install.
WIN10 Preview version in the upgrade the current Technology Preview user can automatically upgrade to a new version, or optionally download an ISO image file installation upgrade. For Win8 old users, Microsoft will launch a new tool (Prepare your PC to get Windows technical Preview), allowing Win8 to successfully eat Windows via Windows Update 10 Technical Preview version or consumption preview version.
This preparation tool (Prepare your PC to get Windows technical Preview) can help Windows 8 users install Windows 10 Technology Preview through Windows Update in the second half of January. But the software official did not specify whether to support the current mainstream Win7.