Steps: 1.Download and install the old version of TA from https://sourceforge.net/projects/tibiaauto/files/tibiaauto/2.73.0/ and install it in, say, C:\Program Files (x86)\Tibia Auto\
Delete the file C:\Program Files (x86)\Tibia Auto\data\tibiaauto-consts.xml(path may vary depending on where you installed it)
Copy the file dowloaded with these instructions (at https://sourceforge.net/projects/tibiaauto/files/tibiaauto/2.74.0/) into the same directory as the deleted file
Then run TA along with the new 10.100 Tibia client.