when can you release the hector_quadrotor for melodic

[ShutingKANG]

I am really want to ask when could you release the hector_quadrotor for melodic. when I run this file spawn_quadrotor_with_downward_cam.launch, there are always some mistakes. can you fix it? for example there is a error like this :
unknown macro name: xacro:quadrotor_plugins None None
when processing file: /home/kang/hector_quadrotor/src/hector_quadrotor/hector_quadrotor_description/urdf/quadrotor_downward_cam.gazebo.xacro
RLException: while processing /home/kang/hector_quadrotor/src/hector_quadrotor/hector_quadrotor_gazebo/launch/spawn_quadrotor.launch:
Invalid tag: Cannot load command parameter [robot_description]: command [/opt/ros/melodic/lib/xacro/xacro '/home/kang/hector_quadrotor/src/hector_quadrotor/hector_quadrotor_description/urdf/quadrotor_downward_cam.gazebo.xacro' base_link_frame:=/base_link world_frame:=world] returned with code [2].

Param xml is
The traceback for the exception was written to the log file

Maybe there is some problem in quadrotor_plugins file.
Thanks for your help.

[tooHotSpot]

Actually there is no limitation to build hector_quadrotor for melodic from sources. This link to article with general installation steps may be helpful: Flying with ROS and Hector.