Unsupported configuration version

This can show as an error or as an warning:

only configurations files on version: 2 are supported, yours is version: 0, please update your configuration

It has to do with the v2 update.

If you get it as a warning, your configuration file is valid in v2, but would benefit with the version header. You can remove the warning by adding this line to your configuration:

version: 2

If you get it as a fatal error, it means your configuration is invalid. You can still add the version header mentioned above, and it'll tell you which parts of the configuration need to be fixed.

You can check the deprecations page to see how to fix them.

Also worth reading the v2 announcement, which contains an upgrade guide.