This is copied out of an internet forum after hearing that duping is still very much possible in .53
The method came up in .51 but appears to still work
Link to the thread:
http://www.unknowncheats.me/forum/dayz-sa/129122-0-51-duplication-dont-jell-reem-2.html
Link to the single post that describes this:
http://www.unknowncheats.me/forum/1099541-post38.html
Note this is just a relaying of information I have not resproduced it myself. But I hate duping and want it gone.