Microsoft released the free public preview version of Windows 8.1 in late June, during the first day of its BUID 2013 conference. In October, Microsoft released the commercial version of Windows 8.1, which was a free download for Windows 8 users and a paid upgrade for all other versions of the OS.
If for some reason you have installed the preview version of Windows 8.1 on one or more of your PCs, it's time to start thinking about upgrading to the final version. In a post this week on the Microsoft Small Business and Development blog, the company stated that the preview license will expire sometime in January 2014.
The blog states:
Plans should be made to move to the released version of Windows 8.1 or return to the prior OS version as soon as possible to avoid interruption in use of the device on which the Windows 8.1 Preview was installed.
The post does not give a specific date in January when the license will shut down, nor does it state how the preview build will behave after deadline has passed. When the license for the preview versions of Windows 8 ended in January, Windows displayed a message to the user saying it will restart Windows every hour until a new product activation key is entered.
Source: Microsoft | Image via Microsoft