• the spawning is now managed by a dedicated "spawner" program [link]
• the "spawner" is launched within the simulation.launch, if you don't use our simulation.launch, then run it manually (todo link to spawner launch)
• spawning is now done via a ROS service call, [new documentation page here]
• use one call for spawning multiple UAVs at once
• the parameters to the spawn command stay the same, they are now just passed via a ROS service
• adding brand new sensors and components no longer requires direct edits in the spawning script. All available parameters are defined in spawner_params.yaml in the format param_name: [default_value, help_description, [list_of_compatible_vehicles]]. The components have to be added into the .xacro model definition as before. All optional parameters are now passed to the .xacro as a pythonic dictionary optionals['param_name']
• the example sessions have been updated [link]
• pulling the simulation repository might need additional actions. The px4 repository will probably have the following uncommitted changes:

$: git status
HEAD detached at d37d20f
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)
  (commit or discard the untracked or modified content in submodules)

        modified:   src/drivers/uavcan/libuavcan (untracked content)

Untracked files:
  (use "git add <file>..." to include in what will be committed)

        cmake/configs/
        msg/tools/gencpp/
        msg/tools/genmsg/
        src/lib/DriverFramework/

no changes added to commit (use "git add" and/or "git commit -a")

the easiest solution is to delete the px4 completely and let it download again, using the following commands:

cd ~/git/simulation/.gitman/
rm -rf px4_firmware
cd ..
gitman install