Microsoft unveiled plans to re-introduce the Start Menu in Windows this Wednesday at it's annual BUILD developer conference, the company had shown off an early pre-release/concept of what they think the Start Menu is going to look like when it rolls round to consumers in an upcoming version of Windows.
Microsoft didn't go into much detail about the new Start Menu, and just said it was simply coming in a future update for Windows 8.1, however Terry Myerson, Microsoft's Executive Vice President of Operating Systems has said in a blog post that we can expect to see the new Start Menu in the next iteration of Windows.
Finally, I previewed some work we are doing for the next iteration of Windows ... In particular, I showed some early thinking on how the user experience in Windows will evolve in a way that will help developers’ apps make their way to users across devices and form factors.
As of this moment, it's unclear what "next iteration" means. It could mean an upcoming update for Windows 8.1, however sources in the past have claimed that the feature will be coming in Windows 9.
Until then, we're just going to have to wait. Microsoft is expected to push out its first major update to Windows 8.1 on April 8th, which introduces a number of new feature such as the ability to pin Modern UI apps on the taskbar, a feature which is obviously pointed at a unified Desktop and Modern UI experiences which has been rumored to be making an appearance in Windows 9.