If an application built for a lower level M580 HSBY CPU can be downloaded & executed in a higher level M580 HSBY CPU?

Yes,an application built for the BMEH582040 is downloadable and executable on the BMEH584040, BMEH586040.
An application built for the BMEH584040 is downloadable and executable on the BMEH586040.

Released for: Schneider Electric USA