question about the app Data Grid Extension (Flex Headers)

I don't know why it always tell me:' Error: unable to find grid with nameError: unable to find grid with name XXX'.   
1 answers

Which Mendix Version are you using? If it’s a newer version, this widget will not work.

The module description says the following:
End of live notice: This widget will not longer be me maintained.

As far as I know, this widget is only working up to mendix 7.4 or something around that.