So today, we are talking about one of the strangest pieces of beta software in mobile history: Windows 10 Mobile Technical Preview build 9928, frequently called "Windows Phone 9" by the community.
According to BetaWiki, this build was originally compiled on 2015-01-21.
Let's dive into!
While this build used to be available as a simple software update, the Insider Program is now dead.
The only way to get this is to manually sideload the update CAB packages using a computer.
After updating, the first thing you will notice is the new boot screen, that replaces the blue Windows Logo of 8.1, with a white/black color scheme "Windows Phone" diciture, similar to how it was on 8.0.
This build features the option to set an image as background, instead of "Tile Picture", giving a glimpse of what the actual Windows 10 Mobile will become.
Fun Fact: the "People" tile can be made as large as 4 x 4 tiles, a feature that we will never see in any stable Windows Phone release.
![]() |
| "People" tile in 4 x 4 |
The Settings icon looks off, as much as the actual app
![]() |
| "System" |
![]() |
| "Display" |
"Windows Phone 9" is a beta that captures the moment Microsoft was trying to ditch Windows 8.1 with something new. This is given by the evident UI Identity Crisis: mixes of modern Windows 10 layouts with 8.1 styles, and system elements.





