diff --git a/src/knx/group_object/group_object.h b/src/knx/group_object/group_object.h
index 4caa44c..09fa81a 100644
--- a/src/knx/group_object/group_object.h
+++ b/src/knx/group_object/group_object.h
@@ -534,7 +534,15 @@ namespace Knx
             // convert new value to given dtp
             uint8_t newData[_dataLength];
             memset(newData, 0, _dataLength);
+
+            const bool encodingDone = true; // TODO FIXME for devel! value.encode needs success indicator
             value.encode(newData);
+            if (!encodingDone)
+            {
+                // value conversion to DPT failed
+                // do NOT update the value of the KO!
+                return false;
+            }
 
             // check for change in converted value / update value on change only
             const bool dataChanged = memcmp(_data, newData, _dataLength);