14 DAY TRIAL // Microsoft will soon launch the new Windows 8.1 OS update, but plenty of people are already running it, mostly following the leaked builds that reached the web in late August.
At this point, Windows 8.1 ISOs are already up for grabs from MSDN and TechNet, but leaked builds continue to be available for download from file-sharing websites.
Even though Microsoft initially wanted to prevent all the leaks and restrict the access to the official builds by releasing the update at the same time for all user categories (including developers), it turns out that the company had a change of heart and even stopped sending takedown requests for leaked ISOs.
So in case you’re looking for details on how to download Windows 8.1 Core, Pro, and N versions, here are the MD5 hashes and builds numbers for file integrity verification purposes:
Windows 8.1 Core and Pro:
Build Number 32-bit: 6.3.9600.16384.WINBLUE_RTM.130821-1623 MD5 Hash 32-bit: 7DD36FEA0D004ACFEDBDB3A5521EF5FF File name: Windows_8.1_EN-US_x86.ISO
Build Number 64-bit: 6.3.9600.16384.WINBLUE_RTM.130821-1623 MD5 Hash 64-bit: F104B78019E86E74B149AE5E510F7BE9 File name: Windows_8.1_EN-US_x64.ISO Windows 8.1 Core and Pro N (without Windows Media Player, Camera, Music, Video):
Build Number 32-bit: 6.3.9600.16384.WINBLUE_RTM.130821-1623 MD5 Hash 32-bit: D7F0E0456D1ACA485A45FB857014DE34 File name: 9600.16384.130821-1623_x86fre_ClientN_EN-US-IRM_CCSNA_DV5.ISO
Build Number 64-bit: 6.3.9600.16384.WINBLUE_RTM.130821-1623 MD5 Hash 64-bit: A0376344C5ACF9AA789F9F566ECA5554 File name: 9600.16384.130821-1623_x64fre_ClientN_EN-US-IRM_CCSNA_DV5.ISO