Hey Stephen,
The package is the same for both.
With the only difference that for DB Service agent you need to add argument -service when starting the jar.
Prior v21 the DB Service agent was using the AE config (ucsrv.ini) and now its using its own one.
Simply make sure to adjust the config as per your requirement and start it.
java -Xmx1G -jar <agent jar>
The service is started with
java -Xmx1G -jar <agent jar> -service