Please take the following steps to update WebOffice extensions 10.4.
Uninstall of WebOffice extensions
Uninstall the WebOffice extension via Control Panel\Programs\Programs and Features.
Note: If problems occur during uninstall, also consider the notes in chapter Problems with WebOffice extensions 10.4 Uninstall.
Note: If you have installed WebOffice extensions 10.4 with ArcGIS Engine, it will also be uninstalled during the uninstall process of the WebOffice extensions 10.4. To avoid problems during the uninstall/install process, please ensure in that case, that the ArcGIS Engine still exists on the system before uninstalling the WebOffice extensions 10.4.
Installation of the WebOffice extensions
Follow the instructions in chapter Install WebOffice Extensions in order to install the current version of the WebOffice extensions 10.4.