No, we will not announce official support for Windows 10 until Solid Edge ST9 and a future ST8 MP. The target for Windows 10 support is ST8 MP2.
Microsoft released 4 cumulative Windows 10 updates within 3 weeks of the July 29 general availability of Windows 10. Last Wednesday (Aug 19th), Microsoft posted a new Windows 10 Technical Preview (beta/release) that is not yet available to the general public. Until we get a somewhat static Windows 10 operating system for final Solid Edge testing, we are hesitant to announce official Solid Edge support.
With that said, we have been testing Solid Edge ST8 on Windows 10 for months. We have a couple of specific PRs that we will fix in ST8 MP2, but all-in-all ST8 MP0 runs well on Windows 10 and can be successfully used for your WIndows 10 evaluation at this time.
Note: Until the general availability of the Windows 10 August 19th Technical Preview (TP) (mentioned above) on a Windows 10 machine that has never had Solid Edge installed, you may need to manually install Microsoft .NET Framework 3.5 prior to starting the Solid Edge ST8 install. (Microsoft resolved this issue in the August 19th Windows 10 TP.)
If you upgraded your Windows 7 or Windows 8 Solid Edge machine to Windows 10, .NET 3.5 is already installed and ST8 will install fine with or without the August 19th TP.