EndNote is a bibliographic software licensed by the Hong Kong Polytechnic University for use by current PolyU staff and students. When a staff or student leaves the University, they must uninstall the program from their computer.
EndNote 21 for Microsoft Windows
EndNote 21 for Apple Mac OS
The reference libraries created by EndNote X9.3 and later versions, including EndNote 21, can not be opened with earlier versions of EndNote. To share your library with collaborators who are using older versions of EndNote, consider sharing the entire library (references with PDF), sharing a group of references (references only), or exporting a traveling library (references only).
More details can be found here.
Previous version of EndNote installer: