Internal error

[JHarris12345]

Description

Describe the bug

Internal error when using /is upgrade - https://pastebin.com/AfreScMt

Output of /bbox version (Mandatory)

Additional context (Optional)

My config: https://pastebin.com/y6xz06ev

[tastybento]

@JHarris12345 I'm not the author on this, but it's choking because there are no default tiers defined in config.yml because you commented them out. The code assumes they exist so that if the world definitions do not exist then it has something to fall back on. As a workaround, I recommend you uncomment the default definitions and let them exist. If you have a world definition, they should override them anyway.
On the code side, it'd be good @Guillaume-Lebegue to handle the edge case situation where there are no config entries so your get.get. doesn't create a NPE. Or, use another getOrDefault approach.