We recommend to create the C:\TERA\GN4\relX folder where X is the version number, e.g. C:\TERA\GN4\rel6, with required subfolders to store a copy of the BIN folder and the add-ins sources to be recompiled. This provides for the local compilation of add-ins - when you change something in custom add-ins, and it allow you to do testing and compiling locally, i.e. without disrupting production functionalities.

The required subfolders are BIN and SRC.

In the SRC folder create the folder GN4AddIns and then - on the first installation - expand in it the system and the custom add-ins. After you did some changes in custom add-ins, do not replace them anymore with the default ones.