The iconification works with any AES version (even with your old Atari-ST computer). When AES supports iconification, Windom uses directly the AES functionality, when AES does not support iconification, WinDom emulates it. In this case, the iconification is local. In order to have a global iconfication system, WinDom uses the ICFS protocol (Iconify Server by Dirk Haun) to place on the desktop the icon window.
When the iconifier window widget is not available, WinDom uses a special combinaison to emulate it. A click on the closer window widget with the SHIFT key (right or left) pressed sends a WM_ICONIFY message (an iconify request) to the window. A click on the closer window widget with the SHIFT and CONTROL keys simulatly pressed sends a WM_ALLICONIFY message (an iconify all windows request) to the window. This emulation is done by the EvntWindom() function when it receives the AES message WM_CLOSED.