Yesterday we published its first release Update of Windows 8.1 through MSDN. Microsoft's new update comes in .MSU format but also as a standalone ISO, but only for its subscribers MSDN. But as you can see the archives installation of the update are freely distributed on the Internet. Updates are distributed through file-sharing websites.
This means that if you search you will be able to get them updated Windows 8.1 before the official release supposed to come to 8 April, although we do not recommend it.
The Windows Update 8.1 θα παραδοθεί στους τελικούς χρήστες μέσω του Windows Update next weekteam, and it's a good idea to wait until you're sure about the content you're downloading to your computer. If you download the MSDN files check the SHA-1s to make sure you have the original files.
