Integrations using Application Credentials and Configuration via OAuth2 need to update their error handling to correctly handle configuration when the internet is down.

Currently integrations using configuration via OAuth2 call config_entry_oauth2_flow.async_get_config_entry_implementation in async_setup_entry in their __init__.py. Previously when there was no network, this would raise ValueError: Implementation not available, which was a non-retryable error, resulting in the integration needing to be manually reconfigured after internet was restored (see Issues 153956 and 144582). core PR 154579 added config_entry_oauth2_flow.ImplementationUnavailableError and raises it in config_entry_oauth2_flow.async_get_config_entry_implementation when OAuth2 configuration is unavailable because of missing internet. Integrations should catch this error and raise ConfigEntryNotReady. The changed behavior with the new exception will be released in 2025.12.

Here is an example of the migration,

-    implementation = await async_get_config_entry_implementation(hass, entry)
+    try:
+        implementation = await async_get_config_entry_implementation(hass, entry)
+    except ImplementationUnavailableError as err:
+        raise ConfigEntryNotReady(
+            "OAuth2 implementation temporarily unavailable, will retry"
+        ) from err

New integrations will find the correct try / except block generated by python3 -m script.scaffold config_flow_oauth2.

The method convert_interval in TemperatureConverter (allowing conversions between °F and °C intervals) has been deprecated in favor of TemperatureDeltaConverter.convert. The new converter and device class are now the preferred way to deal with temperature intervals.

For details, see core PR 155689 and core PR 147358.

Action translations defined in strings.json are no longer included in responses from the WebSocket get_services command and the REST /api/services endpoint because they were incomplete and the Home Assistant frontend did not use them.

Legacy, untranslated action names and descriptions from services.yaml remain in both the WebSocket and REST responses.

Fetch complete action translations with the WebSocket command frontend/get_translations.

For details, see core PR 147120.

The Python and WS APIs for injecting and modifying statistics have changed.

The following changes have been made to the WS API:

• The WS command recorder/update_statistics_metadata accepts a unit_class that points to the unit converter used for unit conversions. If there is no compatible unit converter, unit_class should be set to null. Not specifying the unit_class is deprecated and will stop working in Home Assistant Core 2026.11.
• The metadata object included in the WS command recorder/import_statistics accepts a unit_class that points to the unit converter used for unit conversions. If there is no compatible unit converter, unit_class should be set to null. Not specifying the unit_class is deprecated and will stop working in Home Assistant Core 2026.11.
• The metadata object included in the WS command recorder/import_statistics accepts a mean_type that specifies the type of mean (0 for no mean, 1 for arithmetic mean, or 2 for circular mean). The mean_type replaces the bool flag has_mean. Not specifying the mean_type is deprecated and will stop working in Home Assistant Core 2026.11.
• The items in the response to the WS commands recorder/list_statistic_ids and recorder/get_statistics_metadata have mean_type and unit_class.
• The has_mean in the items in the response to the WS commands recorder/list_statistic_ids and recorder/get_statistics_metadata is deprecated and will be removed in Home Assistant Core 2026.11.

The following changes have been made to the Python API:

• The function async_update_statistics_metadata accepts a new_unit_class that points to the unit converter used for unit conversions. If there is no compatible unit converter, new_unit_class should be set to None. Not specifying the new_unit_class is deprecated and will stop working in Home Assistant Core 2025.11.
• The metadata object passed to the functions async_import_statistics and async_add_external_statistics accepts a unit_class that points to the unit converter used for unit conversions. If there is no compatible unit converter, unit_class should be set to None. Not specifying the unit_class is deprecated and will stop working in Home Assistant Core 2025.11.
• The metadata object passed to the functions async_import_statistics and async_add_external_statistics accepts a mean_type of type StatisticMeanType that specifies the type of mean (NONE, ARITHMETIC, or CIRCULAR). The mean_type replaces the bool flag has_mean. Not specifying the mean_type is deprecated and will stop working in Home Assistant Core 2026.11.
• The items in the return value of the function async_list_statistic_ids have mean_type and unit_class.
• The has_mean in the items in the return value of the function async_list_statistic_ids is deprecated and will be removed in Home Assistant Core 2026.11.

The device filter option is no longer supported by the target selector and has been removed from the target selector documentation.

Hassfest has been updated to fail on services with device filter on targets.

Validation of target selectors that specify a device filter will fail in Home Assistant Core 2026.11.

Background​

Core helpers that extract entities from targets did not support the device filter. When the user picked a floor, area, label, or category, the filter was ignored. The frontend also ignored the device filter when selecting entities for a target.

A review of all core integrations found no correct use of a device filter on target selectors. We removed the device filter from the target selector rather than implement support for it in Core and the frontend.

Impact on custom integrations and blueprints​

Update custom integrations and blueprints to remove device filters from target selectors.

If you have a valid use case for device filters on target selectors, reach out on Discord.

The update coordinator with debouncer active will now accept a request for an update while an update is currently in progress. The request will be queued up to be performed after the current update finishes.

Consider the following case:

async def _update():
    a = await get_a()
    # A: User or other logic request a new update here through async_schedule_update()
    b = await get_b()
    return (a,b)

A user or code that request an updates at timestamp A expects that the entities linked will all get new data from that time. However, since we previously ignored that request, entities would have data for the value of a that is from a time before the update request that was ignored.

To make sure we avoid this case, the update coordinator will now schedule an additional update, if a request is received while currently executing an update.

A side effect of this is that it is now possible to schedule an update from inside an update function of the coordinator. That is useful if for example a connection is lost mid update, and we want all entities to indicate directly as unavailable, yet we want to attempt a re-connect as quick as possible but do that in the next update cycle.

Platform entity services should be registered by calling the helper service.async_register_platform_entity_service from the integration's async_setup instead of calling platform.async_register_entity_service during platform set up.

Existing integrations should be migrated to the new API to ensure loading the services does not depend on platform setup.

For examples of migrating, see core PR 152172 and core PR 152047.

Summary of changes​

Providing hass argument to the following service helpers is deprecated: verify_domain_control, extract_entity_ids, async_extract_entities, async_extract_entity_ids, and async_extract_config_entry_ids.

Since release 2025.1 (via core PR #133062), a reference to HomeAssistant is available as a property of the ServiceCall object, and it became redundant to pass the hass object to the above helpers.

To update your integration, just remove the hass argument.

Support for the hass argument will be removed in Home Assistant 2026.10.

Examples​

ID extraction helpers​

# Old
# target_entry_ids = await async_extract_config_entry_ids(hass, service_call)
# entity_ids = await async_extract_entity_ids(hass, service_call)
# entities = await service.async_extract_entities(hass, platform_entities.values(), service_call)

# New
target_entry_ids = await async_extract_config_entry_ids(service_call)
entity_ids = await async_extract_entity_ids(service_call)
entities = await service.async_extract_entities(platform_entities.values(), service_call)

Decorator helper​

# Old
# @verify_domain_control(hass, DOMAIN)
# async def do_action(call: ServiceCall) -> None:
#     ...

# New
@verify_domain_control(DOMAIN)
async def do_action(call: ServiceCall) -> None:
    ...

One preferred encoding to represent μ in units of measurement​

The unit prefix μ is used by unit of measurement constants like μV and μS. There are however two different Unicode encodings of μ:

1. The MICRO SIGN
2. The Greek Small Letter Mu

Home Assistant previously mixed the two encodings, which caused issues because string comparisons between the two encodings would fail causing unit of measurement validations to fail.

We chose the "Greek Small Letter Mu" because the "MICRO SIGN" encoding is there for compatibility with old 8-bit western European character sets, and the unicode consortium recommends against using it.

With #144853 we have fixed this in the core of Home Assistant by consequently using the Greek Small Letter Mu version to encode μ. In Python literal strings this variant is encoded as "\u03bc".

Developers should check if their code and libraries have a dependency with the ambiguous MICRO SIGN (μ) "\u00b5", and migrate their code to use the Greek Small Letter Mu "\u03bc" instead to avoid issues.

The sensor and number entity platforms now include a built-in feature to automatically convert units that use the ambiguous MICRO SIGN (μ) encoding.

Find instances in Visual Studio Code​

In Visual Studio Code, enable Match Case in the Search (files) panel to find only the chosen encoding. Copy the exact μ character from above and paste it into the search box. The editor’s page search matches all variants; use the global search instead.

New linter​

To avoid issues with new or changed code, #144853 adds a linter that warns about incorrect literal assignments using the non-preferred encoding of μ.

The DeviceEntry.suggested_area attribute is deprecated and will be removed in HA Core 2026.9. Also, suggested_area will no longer be present in EVENT_DEVICE_REGISTRY_UPDATED events when HA Core 2026.9 is released.

Note: Setting suggested_area in DeviceInfo, and passing suggested_area to DeviceRegistry.async_get_or_create is still supported and influences the area of created devices, although that may change in the future.

Use DeviceEntry.area_id to determine a device’s area in custom integrations. Don’t access DeviceEntry.suggested_area.

During the deprecation period, accessing DeviceEntry.suggested_area will log a warning.

For more details, refer to the DeviceEntry documentation and core PR 149730 which deprecated DeviceEntry.suggested_area.