Yes, Windows 8 is actually Windows 6.2, versioning-wise. As I’m sure you remember, Windows 7 is Windows 6.1, and Windows Vista was Windows 6.0.
Don’t be surprised if Microsoft ends up making the successor of Windows 8, Windows 6.3, because most likely, this is the plan.
The Windows OS version increment can be a source of incompatibilities with existing applications, especially if they’re designed to check for upper bound OS version.
Microsoft is simply doing away with some potential compatibility issues by keeping versioning changes as small as possible.
Remember how well Vista apps ran on Windows 7? Well, the promise from Microsoft is that Windows 7 applications will play just as nice on Windows 8.
“The internal version number for Windows Developer Preview and Windows Server Developer Preview is 6.2. All of the versioning APIs will return this version number (GetVersion, GetVersionEx),” the company said.
This is an important piece of information for app developers that can easily tweak their projects in order to make sure that users will have no problems running them on Windows 8.
It’s also good practice for the Windows client that will succeed Windows 8, let’s call it Windows 9 since they’re all codenames after all, and for which Microsoft will use a similar versioning strategy.
Here’s what devs need to keep in mind when it comes to ensuring that their apps deal with the version change in Windows 8:
“Generally, apps should not perform operating system version checks. If an app needs a specific feature, it is preferable to try to find the feature, and fail only if the needed feature is missing.
“At a minimum, apps should always accept version numbers greater than or equal to the lowest supported version of the operating system. Exceptions should occur only if there is a specific legal, business, or system-component requirement.”
Windows 8 Developer Preview Build 8102 Milestone 3 (M3) is available for download here.