What you need to know about Windows 10 Timeline, Sets, and RS5

Kip Kniskern

Windows 10 Logo Generic Featured Image Hero

We still don’t have our hands on the first iterations of Timeline and Tabs, Microsoft’s twin new features that bring an easily accessible “history” to just about everything you do on Windows 10 (Timeline), and add tabs to UWP apps and even File Explorer (Tabs). Yesterday, Microsoft delayed the release of the latest Windows Insider build (again), and now Insiders will have to wait until next week to get our first look at the new features.

It’s easy to bundle the two new features in together, as they were announced together in an email to Insiders by Terry Myerson (the same email that introduced the controversial topic of “A/B” testing). But there’s another reason to think of them together, at least according to noted Microsoft leaker WalkingCat:


If WalkingCat is right, it’s interesting to think of a single backend platform running both Tabs and Timeline. That also makes the timing of these feature releases make a bit more sense, here’s why:

Microsoft dropped a couple of bombshells with Terry Myerson’s email, the first dealing with A/B testing, and then going on to mention that Sets may not make RS4:

And like all features we ship into WIP, they will be broadly available when they are ready, not necessarily tied to the next major update

Sets (which we’ll use here to refer to Sets, Tabs, and Timeline, and readily agree with Microsoft that the naming needs work!) looks to be platform level addition to Windows 10, if not in actual code, then in scope. We expect there to be developer opportunities for creating Sets, for example, both internally and externally, and if Tabs are just “Sets,” or views of a group of files in File Explorer, for example, exposed in the UX, then that’s going to be a lot of work in adding to the basic building blocks of Windows.

All this work is going to take time, and Microsoft is looking forward to getting early feedback from Insiders. That we all won’t have an early opportunity to provide feedback kinda sucks (although we’ll be providing plenty of feedback here at OnMSFT, regardless of whether we have the bits or not), but using A/B testing does provide Microsoft some useful and important information.

That Sets may well not make it to full release until RS5, well that both sucks and is understandable too. This is big, fundamental work, with a profound impact on how we use, share, and store information, and how Microsoft utilizes their understanding about how information both is and can be used.

Here at OnMSFT, we’re excited to see where Microsoft is heading with Sets, and how it works. We’re also excited to be able to help shape the direction and the scope of Sets, and can’t wait to get started. Are you excited to get to testing, too?