Drone 0.5 reached stable API state, so would be worth upgrading. Things to keep in mind:
Once the server is upgraded (it's on my host, drone.osgeo.kbt.io) the .drone.yml files in user repositories should also be updated and possibly agents should also be updated.
There are currently agents on my own laptop, on debbie.postgis.net (@robe) and on @bjornharrtell machine.
\cc @robe, @bjornharrtell
Server upgraded, agents need to upgrade too (done on mine and Debbie, to be done on @bjornharrtell machine).
Part of the upgrade is adapting DRONE_SERVER