diff --git a/pyhap/characteristic.py b/pyhap/characteristic.py
index eea50fbb..02f85675 100644
--- a/pyhap/characteristic.py
+++ b/pyhap/characteristic.py
@@ -132,9 +132,12 @@ class Characteristic:
         "service",
         "_uuid_str",
         "_loader_display_name",
+        "allow_invalid_client_values",
     )
 
-    def __init__(self, display_name, type_id, properties):
+    def __init__(
+        self, display_name, type_id, properties, allow_invalid_client_values=False
+    ):
         """Initialise with the given properties.
 
         :param display_name: Name that will be displayed for this
@@ -150,6 +153,15 @@ def __init__(self, display_name, type_id, properties):
         """
         _validate_properties(properties)
         self.broker = None
+        #
+        # As of iOS 15.1, Siri requests TargetHeatingCoolingState
+        # as Auto reguardless if its a valid value or not.
+        #
+        # Consumers of this api may wish to set allow_invalid_client_values
+        # to True and handle converting the Auto state to Cool or Heat
+        # depending on the device.
+        #
+        self.allow_invalid_client_values = allow_invalid_client_values
         self.display_name = display_name
         self.properties = properties
         self.type_id = type_id
@@ -185,14 +197,22 @@ def get_value(self):
             self.value = self.to_valid_value(value=self.getter_callback())
         return self.value
 
+    def valid_value_or_raise(self, value):
+        """Raise ValueError if PROP_VALID_VALUES is set and the value is not present."""
+        if self.type_id in ALWAYS_NULL:
+            return
+        valid_values = self.properties.get(PROP_VALID_VALUES)
+        if not valid_values:
+            return
+        if value in valid_values.values():
+            return
+        error_msg = f"{self.display_name}: value={value} is an invalid value."
+        logger.error(error_msg)
+        raise ValueError(error_msg)
+
     def to_valid_value(self, value):
         """Perform validation and conversion to valid value."""
-        if self.properties.get(PROP_VALID_VALUES):
-            if value not in self.properties[PROP_VALID_VALUES].values():
-                error_msg = f"{self.display_name}: value={value} is an invalid value."
-                logger.error(error_msg)
-                raise ValueError(error_msg)
-        elif self.properties[PROP_FORMAT] == HAP_FORMAT_STRING:
+        if self.properties[PROP_FORMAT] == HAP_FORMAT_STRING:
             value = str(value)[
                 : self.properties.get(HAP_REPR_MAX_LEN, DEFAULT_MAX_LENGTH)
             ]
@@ -241,6 +261,7 @@ def override_properties(self, properties=None, valid_values=None):
 
         try:
             self.value = self.to_valid_value(self.value)
+            self.valid_value_or_raise(self.value)
         except ValueError:
             self.value = self._get_default_value()
 
@@ -265,6 +286,7 @@ def set_value(self, value, should_notify=True):
         """
         logger.debug("set_value: %s to %s", self.display_name, value)
         value = self.to_valid_value(value)
+        self.valid_value_or_raise(value)
         changed = self.value != value
         self.value = value
         if changed and should_notify and self.broker:
@@ -280,6 +302,8 @@ def client_update_value(self, value, sender_client_addr=None):
         original_value = value
         if self.type_id not in ALWAYS_NULL or original_value is not None:
             value = self.to_valid_value(value)
+        if not self.allow_invalid_client_values:
+            self.valid_value_or_raise(value)
         logger.debug(
             "client_update_value: %s to %s (original: %s) from client: %s",
             self.display_name,
@@ -287,13 +311,14 @@ def client_update_value(self, value, sender_client_addr=None):
             original_value,
             sender_client_addr,
         )
-        changed = self.value != value
+        previous_value = self.value
         self.value = value
-        if changed:
-            self.notify(sender_client_addr)
         if self.setter_callback:
             # pylint: disable=not-callable
             self.setter_callback(value)
+        changed = self.value != previous_value
+        if changed:
+            self.notify(sender_client_addr)
         if self.type_id in ALWAYS_NULL:
             self.value = None
 
diff --git a/tests/test_characteristic.py b/tests/test_characteristic.py
index 25a8b5ba..828e73f5 100644
--- a/tests/test_characteristic.py
+++ b/tests/test_characteristic.py
@@ -72,7 +72,7 @@ def test_to_valid_value():
         PROPERTIES.copy(), valid={"foo": 2, "bar": 3}, min_value=2, max_value=7
     )
     with pytest.raises(ValueError):
-        char.to_valid_value(1)
+        char.valid_value_or_raise(1)
     assert char.to_valid_value(2) == 2
 
     del char.properties["ValidValues"]
@@ -353,6 +353,18 @@ def test_client_update_value():
         assert len(mock_notify.mock_calls) == 3
 
 
+def test_client_update_value_with_invalid_value():
+    """Test updating the characteristic value with call from the driver with invalid values."""
+    char = get_char(PROPERTIES.copy(), valid={"foo": 0, "bar": 2, "baz": 1})
+
+    with patch.object(char, "broker"):
+        with pytest.raises(ValueError):
+            char.client_update_value(4)
+
+        char.allow_invalid_client_values = True
+        char.client_update_value(4)
+
+
 def test_notify():
     """Test if driver is notified correctly about a changed characteristic."""
     char = get_char(PROPERTIES.copy())