Exception after move to new host

[thomaspries]

I had to move from Ubuntu 24.10 to a new host with Ubuntu 24.04:

• Netbox: 4.2.7 => 4.2.7
• Python: 3.12.7 => 3.12.3
• Django: 5.1.8 => 5.1.8
• Postgres 16.9 => 16.10

I followed Replicating NetBox and everything works well without any error. I also moved Netbox to a subfolder netbox/ on the webserver.

After logging in, I realized two things:
a) Plugins are missing
b) an exception while opening the devices

to b) the exception says:

'NoneType' object has no attribute 'objects'
Python version: 3.12.3
NetBox version: 4.2.7
Plugins: None installed

=> I tried to install the plugins:
a1) NetBox IP Fabric:

• source /opt/netbox/venv/bin/activate => OK
• pip install ipfabric-netbox => OK
• "... /opt/netbox/netbox/netbox/configuration.py, add the plugin to the PLUGINS list ..." => OK
• "... Still from the NetBox virtual environment ... python3 /opt/netbox/netbox/manage.py migrate..." => exception:

(venv) root@checkmk:/opt/netbox/netbox# python3 /opt/netbox/netbox/manage.py migrate
Traceback (most recent call last):
  File "/opt/netbox/netbox/manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/django/core/management/__init__.py", line 442, in execute_from_command_line
    utility.execute()
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/django/core/management/__init__.py", line 416, in execute
    django.setup()
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/django/apps/registry.py", line 116, in populate
    app_config.import_models()
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/django/apps/config.py", line 269, in import_models
    self.models_module = import_module(models_module_name)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 995, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/ipfabric_netbox/models.py", line 40, in <module>
    from netbox_branching.models import Branch
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/netbox_branching/models/__init__.py", line 1, in <module>
    from .changes import *
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/netbox_branching/models/changes.py", line 22, in <module>
    class ObjectChange(ObjectChange_):
  File "/opt/netbox-4.2.7/venv/lib/python3.12/site-packages/django/db/models/base.py", line 134, in __new__
    raise RuntimeError(
RuntimeError: Model class netbox_branching.models.changes.ObjectChange doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS.
(venv) root@checkmk:/opt/netbox/netbox# 

Q1) I'm not a python expert, how can I fix this?
Q2) I'm lucky to have the old installation to search for the former installed plugins, what do I do without the old installation? How can I find out, witch plugins were installed?

Thanks in advance.
Thomas