Deprecated function: session_set_save_handler(): Providing individual callbacks instead of an object implementing SessionHandlerInterface is deprecated in drupal_session_initialize() (line 245 of includes/session.inc).
Deprecated function: Creation of dynamic property alpha_theme_container::$delta is deprecated in alpha_theme_container->__construct() (line 25 of sites/all/themes/contrib/omega/alpha/includes/base.inc).
The main difference between this and the "Allowed values" or the "Maximum/Minimum" is that even if the value is outside the accepted limits, it will still pass validation. Also, Accepted Limit allows you to set custom warnings for each field.