Hi Gordon,
Thanks. I'm a newbie and have installed Moodle 2.21, so at this stage don't have any idea how much is involved in upgrading to a newer version of Moodle. Since I'm still learning how to use these functions I still have to figure out how useful they are for my purposes. Once I get to the point of find this out I guess I'll get a better idea as to the precise implications of what you wrote. It's a daily steep learning curve.
Tom