When anyone asked me if any specific feature is available in SQL Server 2008 or if any feature will be disabled in future versions of SQL Server, I always pointed to the following list where all the deprecated database engine features are listed.
Deprecated Database Engine Features in SQL Server 2008 R2
Deprecated Database Engine Features in SQL Server 2008
This list is quite helpful and everybody should refer it once. This list has many important details. For example, it suggests “80 compatibility level and upgrade from version 80.” will not be supported in the next version of SQL Server. If you are using SQL Server 2000 even today (by any chance), you will be not able to upgrade that to the next version of SQL Server directly.
It is very important to check if you are using any feature of SQL Server that is in compatibility mode and if you find them in the list above, you need to start working on the replacement suggested in the article. You can monitor the use of deprecated features by using the SQL Server Deprecated Features Object performance counter and trace events.
Let me know which deprecated feature you will miss the most.
Reference: Pinal Dave (https://blog.sqlauthority.com)
After upgrdation to sql 2008 from sql 200, if the compatibility level is set to 80, will the queries that use the deprecated system tables and other deprecated features still work fine?
Yes they will work fine if they are all available for backward compatibility
sorry i meant sql 2000 not sql 200