SQLSERVER 2008 Developer Evaluation to - Licensed Upgrade Question

Hi Experts,

I've recently licensed my 2008 R2 Evaluation Edition to Licensed one using Edition Upgrade Method. Once I upgraded , it doesn't show the Evaluation copy anymore.

SELECT    SERVERPROPERTY('ProductVersion') AS ProductVersion,    SERVERPROPERTY('ProductLevel') AS ProductLevel,    SERVERPROPERTY('Edition') AS Edition;GO

But, when I'm using the below query it still showing the expiry date as below:

SELECT    create_date AS 'SQL Server Install Date',    DATEADD(DD, 180, create_date) AS 'SQL Server Expiry Date'FROM sys.server_principalsWHERE name = 'NT AUTHORITY\SYSTEM'

Even SSMS --> HELP--> About shows the expiration date.

Microsoft SQL Server Management Studio Complete (expires in 36 days)    10.50.1600.1

Even though it was rightly upgraded to Licensed product, but still shows expiration day. Am I missing something? Is this properly licensed instance now?

Thanks