It says here (https://routerboard.com/RBcAP2nD) that the cAP supports 802.3af/at. However, in the brochure about it is nothing (http://i.mt.lv/routerboard/files/cAP_2nD-160826134842.pdf).
It really supports 802.3af/at? Is there a Passive PoE?
It comes with a standard Mikrotik 100Mbit PoE adapter in the box, so that’s supported at least.
Maybe someone at Mikrotik can add the RBcAP2nD to the PoE compatibility table at http://wiki.mikrotik.com/wiki/Manual:TOC/MikroTik_POE_in_compatibility_table ? 
The confusion comes from the fact that cAP-2n was recently replaced with cAP-2nD, which has different specs and now has 802.3af support. PoE compatibility table will be updated soon.