DeviceInfo is now a dataclass

DeviceInfo and ChildDeviceInfo are no longer TypedDicts. They are dataclasses with typed fields, which are read and written as attributes:

device_info = DeviceInfo(identifiers={(DOMAIN, unique_id)}, name="My device")
device_info.sw_version = "1.2.3"
name = device_info.name

This change is included in Home Assistant Core 2026.11.

Reading and writing fields with [], .get(), and .update() still works for now, but it is a compatibility layer which will be deprecated and removed in a later version. Integrations should move to attributes. Some other dict behavior is already gone, as described in what no longer works.

# Old
device_info["sw_version"] = "1.2.3"
device_info.update({"model": "My model", "manufacturer": "My manufacturer"})

# New
device_info.sw_version = "1.2.3"
device_info.model = "My model"
device_info.manufacturer = "My manufacturer"

Reading a field which has not been set returns UNDEFINED, where .get() returned None. See unset fields.

# Old
name = device_info.get("name")

# New
name = device_info.name

# Old
self._attr_device_info: DeviceInfo = {
    ATTR_IDENTIFIERS: {(DOMAIN, unique_id)},
    ATTR_NAME: "My device",
}

# New
self._attr_device_info = DeviceInfo(
    identifiers={(DOMAIN, unique_id)},
    name="My device",
)

import copy

# Old
new_device_info = device_info.copy()
new_device_info["name"] = "Other name"

# New
new_device_info = copy.copy(device_info)
new_device_info.name = "Other name"

# Old
device_registry.async_get_or_create(
    config_entry_id=entry.entry_id, **device_info
)

# New
device_registry.async_get_or_create(
    config_entry_id=entry.entry_id, **device_info.as_dict()
)

A field which has not been set reads as UNDEFINED, not as None, and None is a value like any other. Note that UNDEFINED is truthy, so test it explicitly:

from homeassistant.helpers.typing import UNDEFINED

# Old
if "name" not in device_info:
    device_info["name"] = "My device"

# New
if device_info.name is UNDEFINED:
    device_info.name = "My device"

A field is unset again by assigning UNDEFINED to it:

# Old
del device_info["name"]

# New
device_info.name = UNDEFINED

Only the fields which are set are passed on to the device registry, so an unset field leaves the corresponding value on the device unchanged.

A dataclass is serialized field by field, unset fields included. orjson, which the Home Assistant JSON helpers use, writes every unset field as 0. dataclasses.asdict keeps them as UNDEFINED. Whenever a device info is stored, sent in event data or a WebSocket message, or held by a dataclass which is serialized, use device_info.as_dict(), which returns the fields which are set:

# Old
await store.async_save({"device_info": device_info})

# New
await store.async_save({"device_info": device_info.as_dict()})

Keys which are not device info fields are rejected. Previously they were silently kept, and either ignored or raised a TypeError later, when the device registry was called:

# Raises TypeError: unexpected keyword argument 'id'
device_info = DeviceInfo(**device_payload)

# Raises KeyError: 'config_entry_id' is not a valid DeviceInfo field
device_info["config_entry_id"] = entry.entry_id

Arguments of async_get_or_create which are not device info fields, such as config_entry_id, are passed to the method directly.

DeviceInfo({...}) raises a TypeError: pass the fields as keyword arguments.

Some rarely used dict behavior is gone: copy, setdefault, values, clear, popitem, pop, del device_info[key], merging with | or |=, iterating over a device info, and len(). Testing a field with in keeps working.

A device info is no longer a dict: isinstance(device_info, dict) returns False. Use isinstance(device_info, DeviceInfo), or device_info.as_dict() where a plain dictionary is needed. An empty DeviceInfo() is no longer falsy either.

To check whether a field exists, for example to support older Home Assistant versions, use "via_device_id" in DeviceInfo.__annotations__. __optional_keys__ and __required_keys__ still work, but are part of the compatibility layer.

sensor_device_info_to_hass_device_info() now returns a cached device info, which can be shared with other devices. It cannot be modified, and raises a TypeError if you try. Copy it first, with copy.copy(device_info). If you add the same fields for every advertisement, build and cache your own DeviceInfo instead, so that it is not copied every time.

created_at, default_manufacturer, default_model, default_name, modified_at, and via_device are still accepted, and still log a deprecation warning when the device is created. They are not part of the typed fields, and will be removed in Home Assistant Core 2027.8 (via_device) and 2027.9 (the others). Use manufacturer, model, name, and via_device_id instead.

ChildDeviceInfo is a dataclass in the same way. An entity registers a child device by returning a ChildDeviceInfo, rather than by adding a parent_device_id key to a DeviceInfo:

self._attr_device_info = ChildDeviceInfo(
    identifiers={(DOMAIN, unique_id)},
    name="Outlet 1",
    parent_device_id=parent.id,
)