Hi Sir Arthur, welcome!
It depends on the game-version of the server(s) you wish to join, but most of the online-servers already use the latest game-version. A few are still running 4.10.1m but sooner or later they will update to 4.11.1m too.
So you need to patch your game all the way up to the latest version (4.11.1m) in the correct order.
Links:
- 4.08m can be found on your IL2 1946 game-dvd
-
4.09m also download and install the skins409m.exe
-
4.10m
-
4.10.1m
-
4.11m
-
4.11.1m
Make sure
not to download and install the dedicated server version of these patches!
Always check the install-directory when installing a patch so that the patches install into your IL-2 game-folder. Start the game after each patch and check the game version (lower left corner of the loading-screen) to see if the patch installed correctly.
If you have enough free space on your harddrive I recommend to make a backup-copy of the game-folder after patching so that you don't have to reinstall the game and all the patches again when you need a fresh and clean installation of IL-2 1946 v4.11.1m (to install mods/modpacks for example). You can have as many copies of this folder as you like.