
Upgrading Windows 8.1 Evaluation and Windows Server 2012 R2 Evaluation to Full Versions
Today I want to talk about two ways to upgrade from Evaluation to a full version of Windows - for servers based on Windows Server 2012 R2 and for Windows 8.1 clients. The methods are fundamentally different: for server OSs, the transition was thought out by Microsoft as a simple scheduled operation; for client OSs, the vendor’s idea is to force the user to perform a complete reinstall of the system. The method proposed below will allow you to upgrade the Evaluation version of Windows 8.1 to a complete one without reinstalling it, and, by the way, make the reverse transition from any version of Windows 8.1 to Evaluation with saving applications and data, if you suddenly need to prove yourself honestly using only the Evaluation version to check.
However, let's start with a simple one. The first question is usually asked - why? The fact is that, unlike the Windows 8.1 Evaluation client system, which six months after installation only reminds you of its Evaluation status by pop-up messages and a black desktop background, the server system will restart once an hour, which is already completely unpleasant.
I have installed Windows Server 2012 R2 Evaluation - with a valid or expired trial period. It turns out that the OS has a regular opportunity to upgrade the OS edition, in particular from Evaluation to the full version. You can see which edition is installed using the command:

The screenshot shows that I have installed a trial version of Windows Server 2012 R2 Standard and the trial period has expired. The second command shows that I can upgrade the OS to the full version of Standard or Datacenter. To do this, I just need to enter the serial number - the number from the TechNet page - KMS Client Setup Keys is perfect . I will use the command:

With this team, I will start the process of turning my evaluation version of Standard into a full version of DataCenter. If I indicated the Standard serial number and ServerStandard Edition, I would have gotten the full version of Standard. After rebooting, I see the result by running the command again

Now I can safely perform system activation on my KMS server, and finish the important task of updating the server.
For the client OS, alas, not so simple. The corporation does not allow you to simply download and install the evaluation version and turn it into a full publicly accessible key. The evaluation version of Windows 8.1 is available only in the Enterprise edition, and there is no Russian version, you must install English and add the Russian language interface after installation. Having executed the same commands in Windows 8.1 Enterprise Evaluation that I previously performed in Windows Server 2012 R2 Evaluation, I will not see the possibility of changing the edition:

The next logical idea is to download the image of the full version of Windows 8.1 Enterprise and perform the installation process “on top” with saving applications and settings. However, alas, disappointment awaits us - Microsoft does not allow updating the trial version to the full one with saving data, we are offered a complete reinstall:

However, do not give up. Enthusiasts have long known a tool that allows you to install the Enterprise version on top of any other, whether it is Evaluation, Core or Professional. The same method that worked in the days of Windows 7 to switch from Professional to Enterprise. Let’s tell our OS that it already has a full Enterprise, and we want to perform a Refresh installation with all the applications and settings saved. Open the registry editor and see the value of the two keys (highlighted in red):

Replace EditionID and ProductName with the same values from the full version:

Now, without any reboots, you can restart the OS update process. This time we will have access to various update paths, including saving applications, files and settings:

The installation wizard goes through this step and starts the update process with all settings saved:

Using the KMS server, you can now activate the OS and enjoy the result:

The same mechanism if necessary, it will allow to downgrade as well - from Enterprise to Professional or to Enterprise Evaluation. I hope someone will find this information useful.
However, let's start with a simple one. The first question is usually asked - why? The fact is that, unlike the Windows 8.1 Evaluation client system, which six months after installation only reminds you of its Evaluation status by pop-up messages and a black desktop background, the server system will restart once an hour, which is already completely unpleasant.
How to quickly upgrade Windows Server 2012 R2 Evaluation to the full version.
I have installed Windows Server 2012 R2 Evaluation - with a valid or expired trial period. It turns out that the OS has a regular opportunity to upgrade the OS edition, in particular from Evaluation to the full version. You can see which edition is installed using the command:
DISM /online /Get-CurrentEdition
Next, you can see to which editions you can upgrade this OS from the command line:DISM /online /Get-TargetEditions

The screenshot shows that I have installed a trial version of Windows Server 2012 R2 Standard and the trial period has expired. The second command shows that I can upgrade the OS to the full version of Standard or Datacenter. To do this, I just need to enter the serial number - the number from the TechNet page - KMS Client Setup Keys is perfect . I will use the command:
DISM /Online /Set-Edition:ServerDatacenter /AcceptEula /ProductKey:W3GGN-FT8W3-Y4M27-J84CP-Q3VJ9

With this team, I will start the process of turning my evaluation version of Standard into a full version of DataCenter. If I indicated the Standard serial number and ServerStandard Edition, I would have gotten the full version of Standard. After rebooting, I see the result by running the command again
DISM /online /Get-CurrentEdition

Now I can safely perform system activation on my KMS server, and finish the important task of updating the server.

How to upgrade the evaluation version of Windows 8.1 Evaluation to full?
For the client OS, alas, not so simple. The corporation does not allow you to simply download and install the evaluation version and turn it into a full publicly accessible key. The evaluation version of Windows 8.1 is available only in the Enterprise edition, and there is no Russian version, you must install English and add the Russian language interface after installation. Having executed the same commands in Windows 8.1 Enterprise Evaluation that I previously performed in Windows Server 2012 R2 Evaluation, I will not see the possibility of changing the edition:

The next logical idea is to download the image of the full version of Windows 8.1 Enterprise and perform the installation process “on top” with saving applications and settings. However, alas, disappointment awaits us - Microsoft does not allow updating the trial version to the full one with saving data, we are offered a complete reinstall:

However, do not give up. Enthusiasts have long known a tool that allows you to install the Enterprise version on top of any other, whether it is Evaluation, Core or Professional. The same method that worked in the days of Windows 7 to switch from Professional to Enterprise. Let’s tell our OS that it already has a full Enterprise, and we want to perform a Refresh installation with all the applications and settings saved. Open the registry editor and see the value of the two keys (highlighted in red):

Replace EditionID and ProductName with the same values from the full version:

Now, without any reboots, you can restart the OS update process. This time we will have access to various update paths, including saving applications, files and settings:

The installation wizard goes through this step and starts the update process with all settings saved:

Using the KMS server, you can now activate the OS and enjoy the result:

The same mechanism if necessary, it will allow to downgrade as well - from Enterprise to Professional or to Enterprise Evaluation. I hope someone will find this information useful.