Thanks, I'd missed that. It's also on the Italian site. You have to find the fare, click the red Buy/Acquista button, then at the bottom of the page click on the words Fare Rules/Regole Tariffarie. (this is before you confirm the purchase)

For the dates I checked, Promo and Easy are both T fares
Comfort is a K fare, and Freedom is Y. So, according to that, it would seem only a Freedom fare is upgradable with miles (since the rules say only Y,B,M,H are upgradable that way). That is different from what the telephone agent told me.

On the page after you select "Buy", above the paragraph with the fare rules link, it sometimes states "For the same price travel in Business Easy". That is also a Y fare, but moves you up front without paying the 50k miles round trip. (however it adds restrictions on ticket changes). Business Freedom is the J fare.

I don't see B, M, or H shown any of these fares, at least on the dates I tried.