> I have an application written in D7, Firebird 1.5.2 classic is the
> back end. I used the Interbase components (IBSQL, IBQuery, etc) that
> were native to Delphi to connect to the database.
>
> Would it be feasible to upgrade to Firebird 2.0 with this
> application, or will I need to rewrite it?
>
> If I have to rewrite, what is recommended? ADO?

I suggest you use DBExpress. Delphi 7-2006 support DBX3. While Delphi
2007 support DBX4.

You may consider use DataSnap (Midas) together with DBX.