To date, my information about Windows 8.1 Update 1 has come from sources at Microsoft and from leaks from Russian and Chinese hackers. But this week, finally, I was able to get my hands on a pre-release build of Update 1. And as you might expect, this build reveals a lot more information than we previously knew about this release.

Here's a quick overview of what's immediately obvious in this build (9600.16596).

Start and apps

Start screen – Search and Power Options button. As seen in previous leaks, the Start screen now sports prominent Search and Power Options buttons; the latter triggers a menu with power management (shut down, restart, etc.) options.

Start screen – Mouse improvements. As seen in previous leaks, the Start screen and Apps screen both provide context menus when you right-click with a mouse instead of using the Metro-style app bar as in Windows 8.0 and 8.1.

Start screen - App installed notification. One of the weird things about Windows 8.1 is that newly installed apps no longer pin a tile to the Start screen. So in Update 1, there is now an app installed notification at the bottom left. You can tap this to jump to Apps and find the newly installed app.

Apps screen – Show more apps. Because users complained that the icons in the Apps screen were too big on large displays, Microsoft added a Show More Apps option that bumps up the density of app icons.

PC Settings tile. There is now a PC Settings button on the Start screen by default so you can find this crucial interface more easily. (It was previously available in the Apps screen.)

Metro apps

PC Settings – Control Panel link. There is now a Control Panel link in the navigation bar in PC Settings.

Metro apps – Mouse improvements. If you mouse up to the top of the screen in any Metro app, a black bar appears with a Close button (and in some cases, Minimize as well) on the right.

Desktop

Desktop - SkyDrive tray icon. The SkyDrive tray icon is back! Sadly, icon emblems in the SkyDrive folder are still missing in action.

Desktop – Pin Metro apps. A Store button is pinned to the taskbar by default and you can pin other Metro apps here of course. As expected, these apps simply run full screen.

Desktop – Show Metro apps. Separately from pinning Metro apps to the taskbar, you can also configure the taskbar to show any running Metro apps in the taskbar as well.

I'll have more soon. But Rafael Rivera has also written about another Windows 8.1 Update 1 feature in his own post, Internet Explorer Enterprise Mode. Be sure to check that out.