From the cRc Kosher list

Kosher Dunkin'

Is your order Pareve, DE or Dairy?
Find out before you sip.

Adding milk?

What the labels mean

PPareve

No dairy, no dairy equipment. Fine with or after meat.

DEDairy Equip.

No dairy ingredients, but made on equipment used for dairy. Adding oat or almond milk makes any drink DE.

DDairy

Contains dairy. Dunkin' milk is assumed not Cholov Yisroel. Adding regular milk makes any drink D.

Good to know

Source: cRc Kosher — Dunkin Donuts Drink List (). Kosher Dunkin' is an independent site, not affiliated with Dunkin' or the cRc. When in doubt, ask your rabbi.