Zsync transport - surefish/koreader GitHub Wiki
With the Zsync
plungin multiple Koreader devices in the same Wifi router can transfer documents between each other directly without bothering to copying document files via USB cable in another computer.
After tapping the Publish this document
menu Koreader will share current document to other Koreader devices in your local network.
After tapping the Subscribe documents
menu Koreader will receive documents from other devices in your local network. Before real receiving Koreader will popup a Choose inbox
window and ask you where to save received documents. Long tap on the directory name will set that directory as inbox directory.