If you are using strictly ASCII characters only, then no. All of the default settings should suffice.
But, if you are using any non-ASCII characters, then make sure both client and server agree on a common byte encoding on the wire, ie UTF-8. You can use the TIdIOHandler.DefStringEncoding property, or the AByteEncoding parameter on individual read/write methods. Indy will convert Unicode to wire encoding on writes, and from wire encoding to Unicode on reads.
In the D2007 code, you should also tell Indy which encoding your AnsiString's are using, if different than the OS default. You can use the TIdIOHandler.DefAnsiEncoding property, or the ADestEncoding/ASrcEncoding parameter on individual read/write methods, respectively. Indy will convert ANSI to Unicode to wire encoding on writes, and from wire encoding to Unicode to ANSI on reads.