What software replaces the old Unity Loader?
While Unity Loader still works for upgrading firmware on most Ecostruxure Control Expert PLCs, the newer ones including V4.xx M580s require EcoStruxure Automation Device Maintenance (EADM).
The most recent version of EADM also supports transferring programs and data files to PLCs.
Here is a link to EADM.https://www.se.com/us/en/download/document/EADM/