diff --git a/SUPPORTED.md b/SUPPORTED.md
index 40330d0a..1781442a 100644
--- a/SUPPORTED.md
+++ b/SUPPORTED.md
@@ -66,6 +66,7 @@ Some newer Kasa devices require authentication. These are marked with <sup>*</su
   - Hardware: 1.0 (US) / Firmware: 1.0.10
   - Hardware: 2.0 (US) / Firmware: 1.0.6
   - Hardware: 3.0 (US) / Firmware: 1.0.3
+  - Hardware: 3.0 (US) / Firmware: 1.0.4
 
 ### Wall Switches
 
diff --git a/kasa/tests/fixtures/KP400(US)_3.0_1.0.4.json b/kasa/tests/fixtures/KP400(US)_3.0_1.0.4.json
new file mode 100644
index 00000000..18580f4e
--- /dev/null
+++ b/kasa/tests/fixtures/KP400(US)_3.0_1.0.4.json
@@ -0,0 +1,46 @@
+{
+    "system": {
+        "get_sysinfo": {
+            "alias": "#MASKED_NAME#",
+            "child_num": 2,
+            "children": [
+                {
+                    "alias": "#MASKED_NAME#",
+                    "id": "8006521377E30159055A751347B5A5E321A8D0A100",
+                    "next_action": {
+                        "type": -1
+                    },
+                    "on_time": 0,
+                    "state": 0
+                },
+                {
+                    "alias": "#MASKED_NAME#",
+                    "id": "8006521377E30159055A751347B5A5E321A8D0A101",
+                    "next_action": {
+                        "type": -1
+                    },
+                    "on_time": 0,
+                    "state": 0
+                }
+            ],
+            "deviceId": "0000000000000000000000000000000000000000",
+            "err_code": 0,
+            "feature": "TIM",
+            "hwId": "00000000000000000000000000000000",
+            "hw_ver": "3.0",
+            "latitude_i": 0,
+            "led_off": 0,
+            "longitude_i": 0,
+            "mac": "3C:52:A1:00:00:00",
+            "mic_type": "IOT.SMARTPLUGSWITCH",
+            "model": "KP400(US)",
+            "ntc_state": 0,
+            "obd_src": "tplink",
+            "oemId": "00000000000000000000000000000000",
+            "rssi": -69,
+            "status": "new",
+            "sw_ver": "1.0.4 Build 240305 Rel.111944",
+            "updating": 0
+        }
+    }
+}