I’ve seen this question a few times. With Microsoft’s pending release of A preview version of Windows 8.1 today/tomorrow (June 26th in conjunction with Build) on the Windows Store, there is a lot of talk about Windows 8.1. One of the things that is often asked is why it is called Windows 8.1 rather than being a Service Pack for Windows 8.

The answer is deceptively simple. A Windows Service Pack rolls up all the released updates and hotfixes for that version up to that point. A Service pack could be considered a set of software patches.

The changes being made with Windows Blue/Windows 8.1, however, are not patches or hotfixes and they have not been released that way; they are incremental improvements to the software.

And this is why it is called Windows 8.1, rather than being a Service Pack.