What is the difference between Integrated Security = True and Integrated Security = SSPI?

Question

I have two apps that use Integrated Security. One assigns Integrated Security = true in the connection string, and the other sets Integrated Security = S

Answer 1

Many questions get answers if we use .Net Reflector to see the actual code of SqlConnection :) true and sspi are the same:

internal class DbConnectionOptions

...

internal bool ConvertValueToIntegratedSecurityInternal(string stringValue)
{
    if ((CompareInsensitiveInvariant(stringValue, "sspi") || CompareInsensitiveInvariant(stringValue, "true")) || CompareInsensitiveInvariant(stringValue, "yes"))
    {
        return true;
    }
}

...

EDIT 20.02.2018 Now in .Net Core we can see its open source on github! Search for ConvertValueToIntegratedSecurityInternal method:

https://github.com/dotnet/corefx/blob/fdbb160aeb0fad168b3603dbdd971d568151a0c8/src/System.Data.SqlClient/src/System/Data/Common/DbConnectionOptions.cs