TLS 1.2 has improvements over previous versions of the TLS and SSL protocol which will improve your level of security. By default, Windows Server 2008 R2 does not have this feature enabled. This KB article will describe the process to enable this.
How to Activate TLS 1.2 on Windows Server 2008 R2 and IIS 7.5
There is always that one machine that you cannot upgrade on a current version because some dependencies outside of your control demand that specific configuration. You may postpone the inevitable, but one day you run out of luck. If your box is a web server, that day will come sooner than you think.
Out of the box, IIS on Windows Server 2008 R2 offers Transport Layer Security only in version 1 (TLS 1.0). That version is outdated and should not be used for securing any HTTPS traffic. Unfortunately, you do not see the version your browser uses to connect to a web server and so it may be that this protocol is still active. If this is the case, your users will not be able to visit your web site when all major browsers block that version at the beginning of 2020.
Is your web server affected?
You can check if your web site has this problem with the SSL Server Test or you open the developer tools of Chrome and check the console output:
The connection used to load resources from https://**** used TLS 1.0 or TLS 1.1, which are deprecated and will be disabled in the future. Once disabled, users will be prevented from loading these resources. The server should enable TLS 1.2 or later. See https://www.chromestatus.com/feature/5654791610957824 for more information.
Install the patch for TLS 1.2
When your server is up-to-date with all security patches offered by Microsoft, then you probably already have TLS 1.2 installed. In this case, you can jump to the next section and activate it.
Should you not have all patches installed, you can manually download KB4019276 from the Microsoft Update Catalog.
Activate TLS 1.2
You need to modify the registry to activate TLS 1.2. Therefore, you should first make a backup. Only when you have a backup should you open regedit and go to the registry path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\
There you need to create a few entries. You can do that manually and follow the steps in this little How-To by QuoVadis. Be careful, it will only work if you type all those words correct and make no spelling errors.
As a final step, you need to reboot your machine. If you now visit your site, Chrome should no longer complain about TLS 1.0 or 1.1. A final check in SSL Server Test should show you that TLS 1.2 is active.
As soon as you no longer need TLS 1.0 and the other outdated protocols, you should disable them. You can use the same keys as you used to activate TLS 1.2, but you need to invert the values. DisabledByDefault must now be 1 while Enabled must be a 0.Microsoft Registry
The blocking of TLS 1.0 and 1.1 will give a nasty little surprise in January 2020. If you still run a Windows Server 2008 R2 machine, you should take a few minutes now and activate TLS 1.2. This will make your start into 2020 much less painful.
Your server should now support TLS 1.2.