Defining apps.py name while upgrading from Django 2.X to 3.X

[Omkar D]

In my Django 2.X project, I had the following structure generated by default:

project_name

      ---> animal_app

                 ---> apps.py

                              name = "animal"

                 ---> zebra

                               ---> apps.py

                                           name = "zebra"

Note that zebra is sub-app of animal app, and name is attribute of it's app config.

Now, after upgrading to 3.X, I figured out that I needed to change name="zebra"  to name="animal.zebra"

I wanted to understand why this change is needed and what does it mean? From the docs and release note it is not much clearly stated for the sub-apps.

[Omkar D]

Also want to know if this change is backward compatible? As far as I have implemented and tested, this AppConfig name changed worked fine with both 2.2 and 3.2, please mention this too while answering.