Thanks, @musicmaster.
 
	I think the new code gives me more or less the same error:
 
	Stack trace
	
		
			1. classes/ObjectModel.php:324 source ObjectModelCore->validateFields()
		
	
	
		
			2. classes/ObjectModel.php:755 source ObjectModelCore->getFields()
		
	
	
		
			3. controllers/admin/AdminOrdersController.php:1518 source ObjectModelCore->update()
		
	
	
		
			4. classes/controller/Controller.php:197 source AdminOrdersControllerCore->postProcess()
		
	
	
		
			5. classes/Dispatcher.php:837 source ControllerCore->run()
		
	
	
		
			6. administrator/index.php:63 source DispatcherCore->dispatch()
		
	
1018:     * @throws PrestaShopException
1019:     *
1020:     * @since   1.0.0
1021:     * @version 1.0.0 Initial version
1022:     */
1023:    public function validateFields($die = true, $errorReturn = false)
1024:    {
1025:        foreach ($this->def['fields'] as $field => $data) {
1026:            if (!empty($data['lang'])) {
1027:                continue;
1028:            }
1029:
1030:            if (is_array($this->update_fields) && empty($this->update_fields[$field]) && isset($this->def['fields'][$field]['shop']) && $this->def['fields'][$field]['shop']) {
1031:                continue;
1032:            }
1033:
1034:            $message = $this->validateField($field, $this->$field);
1035:            if ($message !== true) {
1036:                if ($die) {
1037:                    throw new PrestaShopException($message." - ".$this->$field);
1038:                }
1039:
1040:                return $errorReturn ? $message : false;
1041:            }
1042:        }
1043:
1044:        return true;
1045:    }
1046:
1047:    /**