How can you connect to external database using Mysqli or PDO with current application setup? I've tried a lot of things and with both I get errors respectively "mysqli_connect(): Headers and client library minor version mismatch. Headers:50541 Library:50624" for mysqli and namespace errors for PDO. I couldn't find anything which would help me in the code itself.

Your documentation is kind of lacking in case of writing applications.

My bad. Never used namespaces in PHP and I didn't know that I have to do "use PDO" to do PDO :P.