Microsoft is letting software developers know ahead of time of a major change in the kernel version number for Windows 10, which will soon jump from the current 6.4 to 10.0. This change could affect older Windows applications running on the OS.
Earlier this week, online reports claimed that an unreleased version of Windows 10 showed a change in the kernel version to 10.0. The current public build of the Windows 10 Technical Preview, 9879, still has the 6.4 version number. However, a page on Microsoft's MSDN website for Internet Explorer developers does indeed mention the upcoming change to 10.0:
"Developers preparing for Windows 10 should note that the Windows NT value in the UA string will change from 6.4 to 10.0 with the new release. If you have code that depends on the version number, we advise that you update to allow for the new value."
This is the first major change in the kernel version number for Windows in several years, and while the regular user of Windows 10 will likely not notice any direct changes, it might cause some problems for older Windows programs that were coded with the older kernel number in mind.
Microsoft won't change the kernel number on the public build of Windows 10 to 10.0 until early 2015, when the consumer preview of the operating system is likely to be released.