I have some suggestions concerning file management.
First one is that after plugging zotrax usb to print newly added print file, new file is shown at the bottom of the file list on printer screen. It would be better to see the new file at the top of the list.
The second suggestion is when sending a file to the printer through wifi, system doesn’t allow to choose a directory. Instead if you want to add a file to a directory , 1st you have to save it to your pc than from “add a file” tab under MY Device, you choose a directory. It would save some time to be able to choose a directiory during send operation.