I was quick to manually update season 6 config in my local setup,
but today I realized that engine.jar update is also mendatory.
The old engine is reading the updated properties, but not reading the new positions:
["unitInformation"][1]["upgrade']["shieldBonusPerY"]
...
["unitInformation"][2]["upgrade']["cost1"]
["unitInformation"][2]["upgrade']["attackRange"]
So make sure to download the new engine