Integration fails to load after HA upgrade to core 2025.5.3

[skruehoetl]

The problem

After upgrading the HomeAssistant (OS) Core to 2025.5.3 the victron integration fails to load.
Two errors are shown in the log:

• Setup failed for custom integration 'victron': Unable to import component: cannot import name 'pack_bitstring' from 'pymodbus.pdu.pdu' (/usr/local/lib/python3.13/site-packages/pymodbus/pdu/pdu.py)
• Detected blocking call to import_module with args ('custom_components.victron',) in /usr/src/homeassistant/homeassistant/loader.py, line 1053

While the 1st looks like some environment incompatibility (something about pymodbus versions?), the second one sounds like an error in HA itself, which doesn't really make sense to me.

Environment

• Home Assistant Core release with the issue: 2025.5.3
• Last working Home Assistant Core release (if known): 2025.5.2
• Integration version causing this issue: 0.5.0

Problem-relevant configuration dialog

I can no longeraccess the configuration since the integration won't load, so I can screenshot the "not loaded" error message (in German locale).

Traceback/Error logs

1st log entry:

Logger: homeassistant.setup
Quelle: setup.py:344
Erstmals aufgetreten: 23:15:58 (1 Vorkommnis)
Zuletzt protokolliert: 23:15:58

Setup failed for custom integration 'victron': Unable to import component: cannot import name 'pack_bitstring' from 'pymodbus.pdu.pdu' (/usr/local/lib/python3.13/site-packages/pymodbus/pdu/pdu.py)
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/loader.py", line 993, in async_get_component
    comp = await self.hass.async_add_import_executor_job(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        self._get_component, True
        ^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/local/lib/python3.13/concurrent/futures/thread.py", line 59, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/src/homeassistant/homeassistant/loader.py", line 1053, in _get_component
    ComponentProtocol, importlib.import_module(self.pkg_path)
                       ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/util/loop.py", line 201, in protected_loop_func
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.13/importlib/__init__.py", line 88, 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 1026, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/config/custom_components/victron/__init__.py", line 10, in <module>
    from .coordinator import victronEnergyDeviceUpdateCoordinator as Coordinator
  File "/config/custom_components/victron/coordinator.py", line 11, in <module>
    from pymodbus.payload import BinaryPayloadDecoder
  File "/usr/local/lib/python3.13/site-packages/pymodbus/payload.py", line 22, in <module>
    from pymodbus.pdu.pdu import (
    ...<2 lines>...
    )
ImportError: cannot import name 'pack_bitstring' from 'pymodbus.pdu.pdu' (/usr/local/lib/python3.13/site-packages/pymodbus/pdu/pdu.py)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/setup.py", line 344, in _async_setup_component
    component = await integration.async_get_component()
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/loader.py", line 1013, in async_get_component
    self._component_future.result()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/src/homeassistant/homeassistant/loader.py", line 1005, in async_get_component
    comp = self._get_component()
  File "/usr/src/homeassistant/homeassistant/loader.py", line 1053, in _get_component
    ComponentProtocol, importlib.import_module(self.pkg_path)
                       ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/util/loop.py", line 201, in protected_loop_func
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.13/importlib/__init__.py", line 88, 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 1026, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/config/custom_components/victron/__init__.py", line 10, in <module>
    from .coordinator import victronEnergyDeviceUpdateCoordinator as Coordinator
  File "/config/custom_components/victron/coordinator.py", line 11, in <module>
    from pymodbus.payload import BinaryPayloadDecoder
  File "/usr/local/lib/python3.13/site-packages/pymodbus/payload.py", line 22, in <module>
    from pymodbus.pdu.pdu import (
    ...<2 lines>...
    )
ImportError: cannot import name 'pack_bitstring' from 'pymodbus.pdu.pdu' (/usr/local/lib/python3.13/site-packages/pymodbus/pdu/pdu.py)

2nd log entry

Logger: homeassistant.util.loop
Quelle: util/loop.py:77
Erstmals aufgetreten: 23:15:58 (1 Vorkommnis)
Zuletzt protokolliert: 23:15:58

Detected blocking call to import_module with args ('custom_components.victron',) in /usr/src/homeassistant/homeassistant/loader.py, line 1053: ComponentProtocol, importlib.import_module(self.pkg_path) inside the event loop; This is causing stability issues. Please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue For developers, please see https://developers.home-assistant.io/docs/asyncio_blocking_operations/#import_module Traceback (most recent call last): File "<frozen runpy>", line 198, in _run_module_as_main File "<frozen runpy>", line 88, in _run_code File "/usr/src/homeassistant/homeassistant/__main__.py", line 227, in <module> sys.exit(main()) File "/usr/src/homeassistant/homeassistant/__main__.py", line 213, in main exit_code = runner.run(runtime_conf) File "/usr/src/homeassistant/homeassistant/runner.py", line 154, in run return loop.run_until_complete(setup_and_run_hass(runtime_config)) File "/usr/local/lib/python3.13/asyncio/base_events.py", line 706, in run_until_complete self.run_forever() File "/usr/local/lib/python3.13/asyncio/base_events.py", line 677, in run_forever self._run_once() File "/usr/local/lib/python3.13/asyncio/base_events.py", line 2034, in _run_once handle._run() File "/usr/local/lib/python3.13/asyncio/events.py", line 89, in _run self._context.run(self._callback, *self._args) File "/usr/src/homeassistant/homeassistant/setup.py", line 171, in async_setup_component result = await _async_setup_component(hass, domain, config) File "/usr/src/homeassistant/homeassistant/setup.py", line 344, in _async_setup_component component = await integration.async_get_component() File "/usr/src/homeassistant/homeassistant/loader.py", line 1005, in async_get_component comp = self._get_component() File "/usr/src/homeassistant/homeassistant/loader.py", line 1053, in _get_component ComponentProtocol, importlib.import_module(self.pkg_path)

In case of unit ID issue, missing devices or non-updating devices

Additional information

I recently installed the "Solvis Control" integration which also accesses via modbus, so I suspected incompatible library versions. However, the system was working without an error message after the Solvis Control install and reboot. It was not until the 2025.5.3 upgrade that the issue started

[sfstar]

Hello and thank you for opening this issue and giving the detailed description.

Based on my findings it seems that you might be using this integration:
https://github.com/LarsK1/hass_solvis_control
If I'm incorrect please let me know.

It seems that solvis control hass made pymodbus 3.9.2 already manditory:
https://github.com/LarsK1/hass_solvis_control/blob/7f2c9fd274fb31153b992f0c57f2e446436d16d6/custom_components/solvis_control/manifest.json
While homeassistant core still uses 3.8.3:
https://github.com/home-assistant/core/blob/dev/homeassistant/components/modbus/manifest.json

Since, the ha core modbus version is leading you could try reverting to an older version of the solvis_control component.
This integration has begon the preparation for pymodbus 3.9.x support with an major rewrite in #281 (with some of the latest changes presiding locally on my machine) in order to address some of the deprecations in v3.9.x
I will look into if it's possible to make this integration compatible with both 3.9.x and 3.8.3 at the same time.
However, if this is not possible then the integration will recieve 3.9.x support after ha core gets bumped to 3.9.x

Edit:
To clarify upon the behaviour you saw:
Although solvis enforces an newer pymodbus version this is only downloaded after the 2025.5.3 restart due to an integrations requirements (in this case pymodbus 3.9.x) being satisfied on boot of your ha instance after the integration has been configured (i.e. an config entry has been added to your homeassistant instance to start using the integration after install.)
During boot after the install off solvis control the integration was not yet configured and therefore it's pymodbus constraint wasn't yet enforced.
Therefore, although the behaviour seems to be related to the ha core upgrade it would have been triggered by anything that would have triggered an reboot (after solvis_control was setup).

[skruehoetl]

Thank you for the quick and helpful reply! I already suspected something like the pymodbus 3.9.x version incompatibility and your explanation really helped clarifying things. Specifically, the point with the installed/configured status of the Solvis integration was exactly on point - consider me impressed.

Actually, I had HA restore a backup over night to ...

• get the Victron integration back into working state
• roll back to 2025.5.2 and
• reset the installation to a setup without the Solvis integration

After reading your reply, I went and ran the 2020.5.3 upgrade again, and the Victron integration kept working fine (as predicted) after rebooting.

From my side, I can easily live without the Solvis integration (I have the heat pump working via "raw yaml" modbus) until the next release of your integration. It would therefore be perfectly okay for me, if you just close this issue and don't put additional effort into backporting pymodbus 3.9.x support into the current release branch.

Instead, I'll go and ask the Solvis integration's developers to put a note into their README and notify potential users that the integration is using a newer version of pymodbus than what is used on core and that it may break other modbus integrations.

Oh - and - Thanks again!

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 30 days

[skruehoetl]

Solved with latest release. Thanks! 😁