Ardupilot Build Procedure Changed & Bug with recent MAVProxy

Ardupilot SITL Build Procedure Changed
New procedure: need to verify UE4 behavior with this new stable release

git clone https://github.com/ArduPilot/ardupilot.git
cd ardupilot
git checkout Copter-4.0.3
git submodule update --init --recursive
Tools/environment_install/install-prereqs-ubuntu.sh -y
. ~/.profile
./waf configure --board sitl
cd ArduCopter
sim_vehicle.py -w

MAVProxy latest version cause link lost:
To fix

pip install -Iv MAVProxy==1.8.18

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information