SQLServer:Deprecated Features is a performance object that is available since SQL Server 2005. The number of deprecated features have definitely increased since SQL Server 2005. In SQL Server 2012, there are a number of deprecated features whose use on your SQL Server 2012 instance can be determined through the use of this performance object.

Some of the common features that you might be interested in finding out the usage are DBCC REINDEX, DBCC SHOWCONTIG, DBCC INDEXDEFRAG. Once you have found the usage of these, you can find out which application uses this by looking up the SQL Server default trace.

Example:

declare @tracename nvarchar(4000)

select @tracename = path from sys.traces where id = 1
select TextData, StartTime, EndTime, spid, ServerName, HostName, error, SessionLoginName ,ApplicationName, TransactionID
from fn_trace_gettable(@tracename,default)
where EventClass = 116
and (TextData like '%showcontig%' or TextData like '%reindex%' or TextData like '%indexdefrag%') 

Download the T-SQL script to find out the deprecated features being used on your SQL Server 2012 instance using the script below.

Script name: Deprecated_Features.sql

The above is a good way to determine the use of deprecated features and which requires a change in your SQL Server environment.

References
Discontinued Engine Features in SQL Server 2012
http://msdn.microsoft.com/en-us/library/ms144262.aspx
Deprecated Engine Features in SQL Server 2012
http://technet.microsoft.com/en-us/library/ms143729(SQL.110).aspx