Using Sub-Directories for Default_controller

As far as I understand, the default_controller would not work with subdirectories, look here:
https://github.com/bcit-ci/CodeIgniter/issues/2849

As narfbg mentioned:

Then it's working just fine, 'default_controller' can be either just the controller name or a controller/method pair. That you had it working with a directory in 2.1.x is a bug and not the intended behavior.

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