No major visual improvements are made to Windows 8.1 build 9477, so it was most likely developed to fix bugs and other problems reported by users in the previous versions.
This version does come, however, with some slight changes on the Start screen, including different colors and icons for the Mail and Help & Tips apps.
The font also appears to be bigger, but this could actually be a modification made to the Chinese version. Build 9477 is currently available in Chinese language only, but with a few tricks, switching to English is also possible.
Otherwise, Windows 8.1 remains practically unchanged, as Microsoft probably spends a lot more time trying to improve the overall performance of the app.