Bernd,

The OCX can open/use a report definition that is older than the version that was current when the OCX was constructed but not the other way around

so:
- If the customer has a 6.2 OCX you can use the report structure version 41
- If the customer has a 6.1 OCX you cannot use the report structure version 41

BUT, it is always better to update the report definition to match with the OCX version as (small) differences may be in place that would be otherwise catched when you test the upgraded report

PS: With the release of v8.1 version 6.2 of DataFlex Reports is no longer a supported version