Database access version 4 doesn't work

There are nothing stopping you from using PDO outside of CodeIgniter database library. Those listed in the documentation are what CodeIgniter database library can connect to.

I'm just guessing that you mean plain queries when you mean PDO right? That you used $this->db->query? Are that what you mean by PDO?
If so, you can still do all those things, but with the mysqli driver.

Now that I get to looking at the code, it seems I converted all the PDO calls to CI style calls.  I forgot about that.  I wrote this about 4 years ago and for various reasons, the folks I wrote it for dumped it after a year, so I haven't looked at it for a while.  I have a new project and am stealing some of the logic and views from that older project.  I guess my concerns aren't all that important any longer.

Thank you for your help.
Jim.