Isn't it 2022 software for returns beginning in 2022? (My brain's fried right now, but giving you something to research.) And, I don't use ATX, but I e-filed Form 7004 in ProSystem fx.
The key is he cannot take possession of the land until the building is completed.
I don't think the article mentioned another strategy where contractor buys land (not the existing land) and constructs the building before the exchange takes place.