All these new S7 Batchs for sale... makes me wonder if they are just trying to sell off their used S7 machines that they were mining with as they replace their own farms with the the new S9 miners.  "refurb" the used S7, clean them up, maybe make a few slight cost effective modifications here and there .. and sell it as a "new batch" just to get rid of the S7 they were mining with?

I mean, what has really changed in these last two batches? went back two fans? anything else?