Error Message after migrating from 3.0 CI 3.0rc3

I have been using CI 3.0 for a while and just upgraded to 3.0 rc3. After that I got this error message

A PHP Error was encountered

Severity: 8192

Message: mysql_pconnect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead

Filename: mysql/mysql_driver.php

Line Number: 135

Backtrace:

File: C:\wamp\www\oph_production\index.php
Line: 292
Function: require_once

What could that be?

... what the message says.

Has nothing to do with CI though, that's coming from PHP. Were you using mysql driver before or mysqli or pdo? Switch to mysqli or pdo and it will go away.

Thank you CroNix! Case closed!