[Bug]: HA 2025.9: ModbusClientMixin.read_holding_registers() got an unexpected keyword argument 'slave'

[dherzog90]

Describe the issue

The integration does not load after updating to HA 2025.8 - there seems to be an modbus error.

Describe your Huawei Solar Setup

Inverter Type: Huawei SUN2000 10KTL M1
Inverter Firmware version: V100R001C00SPC172
sDongle present: Yes
sDongle Type: sDongleA-05 (Ethernet)
sDongle Connectivitiy: Ethernet
sDongle Firmware: V200R022C10SPC300
Power meter present: three phase
Optimizers Present: No
Battery: None
Battery Firmware version:
Huawei Solar integration version: 1.5.5

How do you connect to the inverter?

Via the SDongle, wired connection

Upload your Diagnostics File

Cant download the diagnostics because the integration is not loading

Upload your relevant debug logs

Logs from HA: 
Logger: homeassistant.config_entries
Source: config_entries.py:749
First occurred: 09:22:00 (2 occurrences)
Last logged: 09:30:16

Error setting up entry SUN2000-10KTL-M101074311-0 for huawei_solar
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/config_entries.py", line 749, in __async_setup_with_context
    result = await component.async_setup_entry(hass, self)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/config/custom_components/huawei_solar/__init__.py", line 96, in async_setup_entry
    primary_bridge = await create_tcp_bridge(
                     ^^^^^^^^^^^^^^^^^^^^^^^^
    ...<3 lines>...
    )
    ^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 659, in create_tcp_bridge
    return await _create(await AsyncHuaweiSolar.create(host, port, slave_id), slave_id)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 685, in _create
    product_info = await HuaweiSolarProductInfo.retrieve_from_device(client, slave_id)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 67, in retrieve_from_device
    ) = await client.get_multiple(
        ^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<8 lines>...
    )
    ^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 292, in get_multiple
    response = await self._read_registers(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<3 lines>...
    )
    ^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 429, in _read_registers
    return await _do_read()
           ^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/backoff/_async.py", line 151, in retry
    ret = await target(*args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/backoff/_async.py", line 151, in retry
    ret = await target(*args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 377, in _do_read
    response = await self._client.read_holding_registers(
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        register,
        ^^^^^^^^^
        count=length,
        ^^^^^^^^^^^^^
        slave=slave or self.slave_id,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
TypeError: ModbusClientMixin.read_holding_registers() got an unexpected keyword argument 'slave'

Please confirm the following:

• I'm running the latest release of Home Assistant.
• I'm running the latest release of this integration.
• I did not find an existing issue describing this problem.
• I did upload the diagnostics-file that I could retrieve from the 'Devices & Services Page'
• I did upload the relevant debug logs (via 'Enable Debug Logging'-feature or by manually configuring HA logging)

[dherzog90]

I am using also another integration which uses modbus - there are also errors since HA update to 2025.8: pail23/stiebel_eltron_isg_component#421

[Adp4432]

I have the same problem, Huawei Solar integration could not be loaded after HA 2025.8 update.

2025-08-08 10:49:31.579 ERROR (SyncWorker_6) [homeassistant.util.package] Unable to install package huawei-solar==2.4.4: error: Failed to fetch: https://files.pythonhosted.org/packages/c1/f9/6c2fadb181492942cb0ab84163e726741cae39bd8fe76f069d3690ce5b2e/huawei_solar-2.4.4-py3-none-any.whl.metadata
2025-08-08 10:49:31.582 ERROR (MainThread) [homeassistant.setup] Setup failed for custom integration 'huawei_solar': Requirements for huawei_solar not found: ['huawei-solar==2.4.4'].

[sky-future]

I have the same error ! After Home assistant update.

[wlcrs]

What other integrations do you use Modbus under the hood?

[dherzog90]

i am using this integration which uses modbus for communication with heat pumps: https://github.com/pail23/stiebel_eltron_isg_component

[Adp4432]

I also use Modbus Tcp to communicate to a heat pump, but direct from NodeRed in HA. But this works ok after the update.

[wlcrs]

The root cause of this issue is that an incompatible version of pyModbus is installed in your HA environment. This is typically caused by another (custom) component that requires a conflicting version.

My policy is to stay compatible with the pymodbus-version that is required by the native modbus integration of HA. In HA2025.8, the pymodbus version is 3.9.2. I just saw that the version was bumped by the modbus-integration maintainer to 3.11.0, which will most probably release in HA2025.9 . This release contains the breaking argument name change that causes the issue here.

I will make sure to time the release of a new version around the same time to minimize possible disruption.

I'm sorry for the inconvenience caused, but this "dependency hell" is an inherent part of the Python ecosystem on which HA is built.

[jagoman81]

I have the same problem.
Do we have to do something with our HA installation to solve the situation, or just wait for integration update or HA new release.
I used the integration to optimize my energy consumption to be directly from solar production.
Thank you!

[LotharWoman]

It can't be the wrong pymod bus alone. I do not use any further integration and only the entities of DTSU and "batterie 1" entities are affected. Inverter and "batteries" entities, on the other hand, work fine.

[jagoman81]

Downgraded to HA Core 2025.7.3 and Integration runs well again. So problem is in Core 2025.8.0

[henfri]

I'm sorry for the inconvenience caused, but this "dependency hell" is an inherent part of the Python ecosystem on which HA is built.

@wlcrs it is particularly Bad for pymodbus.
pymodbus-dev/pymodbus#2625

Do not understand, why API ist constantly changing without proper Backwards compatibility.

[rosenhei64-byte]

I'm experiencing the same problem on my installation.
I also have the stiebel_eltron_isg_component installed.
After downgrading to HA 2025.7.3, huawei_solar started working again, but the stiebel_eltron_isg component stopped with a similar error.