diff --git a/haco/capabilities.py b/haco/capabilities.py
index 2a09a9f..17b1d83 100644
--- a/haco/capabilities.py
+++ b/haco/capabilities.py
@@ -4,7 +4,7 @@ from typing import TYPE_CHECKING, Type, ClassVar
 
 from pydantic import Field
 
-from corio.iterator_tools import strip_none
+from corio.iterator import strip_none
 
 from haco.base import Base
 from haco.topics import AnnounceTopicState, AnnounceTopicCommand
diff --git a/haco/control.py b/haco/control.py
index bce7d3e..009cd02 100644
--- a/haco/control.py
+++ b/haco/control.py
@@ -6,7 +6,7 @@ from pydantic import Field
 
 from corio import Constants
 from corio import Path
-from corio.json_tools import to_json
+from corio.jsn import to_json
 
 from haco.base import Base
 from haco.capabilities import Capability
diff --git a/haco/obs.py b/haco/obs.py
index 74ade85..b0b1d93 100644
--- a/haco/obs.py
+++ b/haco/obs.py
@@ -3,13 +3,13 @@
 Observability and logging setup for the haco library.
 
 """
-from corio import logging, debug, Constants
+from corio import logs, debug, Constants
 
 from haco.paths import paths
 
 debug.trace()
 
-logger = logging.get_logger(
+logger = logs.get_logger(
     name=paths.name_ns,
     stream=Constants.DEVELOPMENT,
     version=paths.metadata.version,
diff --git a/haco/tests/test_pydantic_models.py b/haco/tests/test_pydantic_models.py
new file mode 100644
index 0000000..1c33d4e
--- /dev/null
+++ b/haco/tests/test_pydantic_models.py
@@ -0,0 +1,84 @@
+from __future__ import annotations
+
+from types import SimpleNamespace
+
+import pytest
+
+from corio import Path
+
+from haco.climate import Climate
+from haco.device import Device
+from haco.switch import Switch
+
+
+@pytest.fixture
+def client_stub():
+    return SimpleNamespace(
+        topic=Path("root/client"),
+        will=SimpleNamespace(topic="root/status"),
+    )
+
+
+def test_switch_announce_payload_matches_expected(client_stub):
+    switch = Switch(name="Main", icon="power")
+    device = Device(name="Dev", controls=[switch])
+    device.set_parent(client_stub)
+
+    data = switch.get_announce()
+    assert data == {
+        "platform": "switch",
+        "name": "Main",
+        "icon": "mdi:power",
+        "unique_id": "dev-main",
+        "availability_topic": "root/status",
+        "state_topic": "root/client/dev/main/default/state",
+        "command_topic": "root/client/dev/main/default/command",
+    }
+
+
+def test_climate_announce_payload_has_expected_ha_keys(client_stub):
+    climate = Climate(name="Cl")
+    device = Device(name="Dev", controls=[climate])
+    device.set_parent(client_stub)
+
+    data = climate.get_announce()
+
+    expected_subset = {
+        "platform",
+        "name",
+        "unique_id",
+        "availability_topic",
+        "temperature_unit",
+        "temperature_min",
+        "temperature_max",
+        "mode_command_topic",
+        "mode_state_topic",
+        "temperature_command_topic",
+        "temperature_state_topic",
+        "power_command_topic",
+        "power_state_topic",
+    }
+    assert expected_subset.issubset(set(data))
+    assert not any(key in data for key in {"capabilities", "subscriptions", "device", "parent"})
+    assert not any(callable(value) for value in data.values())
+
+
+def test_model_dump_excludes_runtime_extra_attributes():
+    switch = Switch(name="Main")
+    switch.dynamic_callback = lambda value: value
+
+    dumped = switch.model_dump()
+    assert "dynamic_callback" not in dumped
+
+
+def test_parent_wiring_sets_control_subscriptions(client_stub):
+    switch = Switch(name="Main")
+    device = Device(name="Dev", controls=[switch])
+    device.set_parent(client_stub)
+
+    assert switch.unique_id == "dev-main"
+    assert switch.availability_topic == "root/status"
+    assert device.subscriptions is not None
+    assert "root/client/dev/main/default/command" in device.subscriptions
+    handler = device.subscriptions["root/client/dev/main/default/command"]
+    assert hasattr(handler, "handle")
diff --git a/haco/utils.py b/haco/utils.py
index f9bb484..67dc687 100644
--- a/haco/utils.py
+++ b/haco/utils.py
@@ -1,8 +1,8 @@
 import string
 from typing import Callable
 
-from corio import json
-from corio.datatype_tools import to_bool
+from corio import jsn
+from corio.datatype import to_bool
 
 CHARS_ALLOWED = string.ascii_lowercase + string.digits
 SEPS = '_- /'
@@ -76,8 +76,8 @@ class ConvertersNumeric(Converters):
     Converters for numeric values.
 
     """
-    command: Callable = json.from_json
-    state: Callable = json.to_json
+    command: Callable = jsn.from_json
+    state: Callable = jsn.to_json
 
 def get_prefix(io: str) -> str:
     """