Index: branches/RC/core/units/custom_data/custom_data_event_handler.php
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diff -u -r11600 -r11623
--- branches/RC/core/units/custom_data/custom_data_event_handler.php	(.../custom_data_event_handler.php)	(revision 11600)
+++ branches/RC/core/units/custom_data/custom_data_event_handler.php	(.../custom_data_event_handler.php)	(revision 11623)
@@ -112,6 +112,7 @@
 				$custom_name = $custom_params['FieldName'];
 				$field_options = Array('type' => 'string', 'not_null' => 1, 'default' => $custom_params['DefaultValue']);
 
+				// raises warnings during 4.3.9 -> 5.0.0 upgrade, no fatal sqls though
 				if ($custom_params['IsRequired']) {
 					$field_options['required'] = 1;
 				}