Are Biodiesel blends exempt from the new Federal ULSD mandate?

I was up in Vermont today and stopped at a Shell Convenient Mart in Brattleboro and filled up with B20. The sticker on the pump...which looked new...said it was a Biodiesel blended with Low Sulfur "highway" Diesel -500ppm sulfur.
Of course the clerks at the cash register had no clue what it was blended with when I asked. Do you think it was an old sticker or does blended Biodiesel not have to comply to the new regs.....a loop hole may be?

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FRED

Daily Driver: 98 E300TD 199K
Hobby Car: 69 Austin Mini
Past Diesels: 84 300SD, 312K
87 300SDL, 251K
94 Chev. K-1500 6.5Ltr.TD, 373K