According to this:

https://community.developer.authorize.net/t5/Integration-and-Testing/Sandbox-URL-to-test-TLS-Update/...

it would appear that transaction requests submitted to https://test.authorize.net/gateway/transact.dll cannot complete if the submitting application is not TLS 1.2 compliant.

Have I understood this correctly?

My application is compiled with Visual Studio 2010 and .NET 4, which, as I understand it anyway, requires a hack to make it work with TLS 1.2. For example, I've read that if the following code (bolded) is implemented in the global.asax file of a .NET 4 application, it will use the proper protocol without incident:

protected void Application_Start(Object sender, EventArgs e)
        {
            // Enforce the security protocol to TLS 1.2

            //System.Net.ServicePointManager.SecurityProtocol = (System.Net.SecurityProtocolType)3072;

            Application["TotalUsers"] = 0;
            Application["CurrentUsers"] = 0;
        }

My quandry has to do with the fact that I just placed my app in test mode, which tests transactions against https://test.authorize.net/gateway/transact.dll and the test went through fine, i.e., I got a TEST MODE receipt from both Authorize.Net and my application.

As you can see, however, the required code is commented out, meaning it shouldn't have been capable of utilizing TLS 1.2?

I'm concerned I'm not seeing something correctly here.

Any help is appreciated.