We updated Ars Magica 2!

First of all , you have to make sure you closed AT Launcher and/or Minecraft.

Open the folder in which you installed AT Launcher
Open Instances folder.
Open Crack Pack 1.7.10 folder (same name as the instance in the instances list) * Depends on client
Open mods folder.
Find 1.7.10_AM2-1.4.0.006.jar and delete it.
Download 1.7.10_AM2-1.4.0.008.jar from http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/1292222-ars-magica-2-version-1-4-0-008-updated-february-6 and place it in the mods folder.
Close the folder and start AT Launcher and have fun !