You only need the latest version (2.1).
Installation procedure:
1) Install official patch 1.09.
2) Unzip IGC 2.1 into your EU directory.
3) Run patch.exe which resides there now.
4) Run IGCConfig.exe which also resides in your EU directory.
5) Start up EU.
Installation procedure:
1) Install official patch 1.09.
2) Unzip IGC 2.1 into your EU directory.
3) Run patch.exe which resides there now.
4) Run IGCConfig.exe which also resides in your EU directory.
5) Start up EU.