"Biodiesel blends up to B20 can be used ONLY if the biodiesel (100% biodiesel or B100) meets ASTM D6751, EN 14214, or equivalent specification."

It calls for engine oil rated "CD" or higher or ACEA E3 or higher. CD tells me there's no DPF or converter. (I guess I could go out and look, but I didn't notice anything like that, and it does smoke a a little on a cold start.)

Found the parts diagram. Doesn't look like there's any room for any aftertreatment.

From the manual:
IMPORTANT:

Avoid damage! Use only ultra-low sulfur diesel (ULSD) fuel with a maximum sulfur content of 15 mg/kg (15 ppm).

It also says you can use either #1 or #2 fuel oil.