You beat me to it.

Following upgrade to 1.56c CEON URI 5.0 is producing a 301 error - store side. Likewise disabling the mod and all's well.

During the upgrade everythings ok with all 1.56c file changes except /includes/auto_loaders/config.core.php - this breaks CEON URI 5.0/ZC

The 1.56c changes to this file seem to be a reordering of init_sanitize.php and init_script.php.

edit: on a local machine using wampserver