Symptoms
When you use XMLSerializer to serialize the System.Security.Authentication.SslProtocols type value, you encounter a System.InvalidOperationException error.
Cause
This issue occurs because in the .NET Framework 4.6.2 Preview, ObsoleteAttribute was added to a few members (SSL2, SSL3) of System.Security.Authentication.SslProtocols Enum. Because XMLSerializer doesn't support ObsoleteAttribute, it throws and InvalidOperationException error.
Resolution
The issue will be fixed in the .NET Framework 4.6.2 future release by removing the ObsoleteAttribute from System.Security.Authentication.SslProtocols.
For more information about the Microsoft .NET Framework 4.6.2 Preview, see the .NET Framework 4.6.2 Preview known issues.
More Information
For more information, see Application compatibility in the .NET Framework 4.6.2.
