Argument 1 passed to Kitchenu\Debugbar\SlimDebugBar::__construct() must be an instance of Interop\Container\ContainerInterface, instance of Slim\Container given

[sovantha]

I was upgrading my Slim/Slim package from 3.8 to 3.12 then the Slim-DebugBar failed. It turns out that the core slim framework was re-implemented their container interface from Interop\Container\ContainerInterface to Psr\Container\ContainerInterface while the SlimDebugBar class (in 1.1.1) still requires Interop\Container\ContainerInterface in its constructor.
My solution was to change the constructor's parameter type hinting to Psr\Container\ContainerInterface inside the vendor folder (it's not recommended but it does the work).