Windows 8.1 build 9477 (fbl partner out31)

Windows 8.1 build 9477 (fbl_partner_out31) is a build of Windows 8.1.

On 9 August 2013, win8china posted an article about build 9477 being released to partners. It also mentioned that soon, Windows 8.1 will hit RTM Escrow.

On 20 August 20, 2013, a user called 我爱穹妹 posted two screenshots of this build to PCBeta. One of them revealed most of the buildstring, though they censored the time and hash.

On August 21, 2013, the build leaked on PCBeta. It originally leaked in the form of all folders in one .rar file, and the boot folder was missing. There were various attempts to fix it, most of the times using just the regular 9471 boot folder, but JaGoTu's ultimate 9477 patch uses 9477 files where possible.

On 19 October 2018, the build leaked in many languages, including English.