Well from the
product page for the Edge 530 on Garmin's site you click the link that says
"specs" and it takes you to the Edge 530's specification page. Then you go down the list and two up from the bottom you see
SHIMANO DI2 SYNCHRO SHIFT INTEGRATION . Taking that link you can read some more specific info which has fold up you can expand by clicking
Garmin Di2 compatibility list. You'll have to go to that page and click that yourself, it's not a link.
So I think it's a yes that the Edge 530 will handle D-fly or the IEWWU111A. Now whether it will do what you think it does and gives you the info you think it should is a different matter altogether.