We have run through multiple clients websites after the upgrade, and found all the applications run fine (i.e wordpress, joomla, drupal, phpBB).
If you built your own applications and it does not work, we recommend to upgrade to VPS whereby we can customize the VPS with PHP 5.3 and mysql 5.5.
We regret to inform that we are not able to support multiple PHP or downgrade the PHP.
We apologize truly for the inconvenience caused.
If you have any questions, please send an email to firstname.lastname@example.org
Update on this event: PHP migration is cancelled. Will be scheduled at later time due to some website is not compatible.