Default max 12v Compatible
By default board revision up to and v2r6 are either 5v, or, 5v and 12v compatible. The same goes for the pre-assembled versions of these versions (I am considering changing this in a future revision, more testing needs to be done for this!). There is not much headroom in there because the large capacitors are specced at 16v max.
Making it 24v Compatible
Other components on the board, such as the selected DC-DC converter, fuses used, etc.. are compatible up to about 32v. Other components are behind the DC-DC converter (needed for usage above 5v!). To make your board 24v compatible you will only need to replace the 2 big capacitors with capacitors that are rated higher such as 35v like I used in this video. One side will fit perfectly the other will have slightly wrongly spaced holes but as shown in the picture it can be made to fit easily.
35v 1000uF 20mm high Capacitor (20 pieces) (Aliexpess only)