Thanks for your reply, it's much appreciated.
I checked and downloaded the latest versions of all the third party plugins we use before I upgrade the database.
This is the content of the version.php file, it's the one released in June 2014:
defined('MOODLE_INTERNAL') || die();
$plugin->requires = 2011120500;// Moodle 2.2
$plugin->component = 'block_autoattend';// Full name of the plugin (used for diagnostics)
$plugin->cron = 0;
$plugin->maturity = MATURITY_STABLE;
$plugin->version = 2014062600;// The current plugin version (Date: YYYYMMDDXX)
$plugin->release = '2.3.3';
Although I've downloaded the latest versions, some plugins code is out of date, for example in the autoattend block (and mod) I had to replace myself the deprecated functions which is something that should have been updated before releasing this version I believe..
Thanks once again for your help.