diff --git a/homeassistant/components/fronius/const.py b/homeassistant/components/fronius/const.py
index 083085270e0..273f1acab41 100644
--- a/homeassistant/components/fronius/const.py
+++ b/homeassistant/components/fronius/const.py
@@ -42,8 +42,6 @@ class InverterStatusCodeOption(StrEnum):
     IDLE = "idle"
     READY = "ready"
     SLEEPING = "sleeping"
-    UNKNOWN = "unknown"
-    INVALID = "invalid"
 
 
 _INVERTER_STATUS_CODES: Final[dict[int, InverterStatusCodeOption]] = {
@@ -61,13 +59,13 @@ _INVERTER_STATUS_CODES: Final[dict[int, InverterStatusCodeOption]] = {
     11: InverterStatusCodeOption.IDLE,
     12: InverterStatusCodeOption.READY,
     13: InverterStatusCodeOption.SLEEPING,
-    255: InverterStatusCodeOption.UNKNOWN,
+    # 255: "Unknown" is handled by `None` state - same as the invalid codes.
 }
 
 
-def get_inverter_status_message(code: StateType) -> InverterStatusCodeOption:
+def get_inverter_status_message(code: StateType) -> InverterStatusCodeOption | None:
     """Return a status message for a given status code."""
-    return _INVERTER_STATUS_CODES.get(code, InverterStatusCodeOption.INVALID)  # type: ignore[arg-type]
+    return _INVERTER_STATUS_CODES.get(code)  # type: ignore[arg-type]
 
 
 class MeterLocationCodeOption(StrEnum):
diff --git a/homeassistant/components/fronius/strings.json b/homeassistant/components/fronius/strings.json
index 51cb087efc2..e2740c76696 100644
--- a/homeassistant/components/fronius/strings.json
+++ b/homeassistant/components/fronius/strings.json
@@ -86,9 +86,7 @@
           "error": "Error",
           "idle": "Idle",
           "ready": "Ready",
-          "sleeping": "Sleeping",
-          "unknown": "Unknown",
-          "invalid": "Invalid"
+          "sleeping": "Sleeping"
         }
       },
       "led_state": {
diff --git a/tests/components/fronius/snapshots/test_sensor.ambr b/tests/components/fronius/snapshots/test_sensor.ambr
index 700c09da2f6..8f8c9d919fc 100644
--- a/tests/components/fronius/snapshots/test_sensor.ambr
+++ b/tests/components/fronius/snapshots/test_sensor.ambr
@@ -560,8 +560,6 @@
         'idle',
         'ready',
         'sleeping',
-        'unknown',
-        'invalid',
       ]),
     }),
     'config_entry_id': <ANY>,
@@ -605,8 +603,6 @@
         'idle',
         'ready',
         'sleeping',
-        'unknown',
-        'invalid',
       ]),
     }),
     'context': <ANY>,
@@ -3815,8 +3811,6 @@
         'idle',
         'ready',
         'sleeping',
-        'unknown',
-        'invalid',
       ]),
     }),
     'config_entry_id': <ANY>,
@@ -3860,8 +3854,6 @@
         'idle',
         'ready',
         'sleeping',
-        'unknown',
-        'invalid',
       ]),
     }),
     'context': <ANY>,
@@ -7234,8 +7226,6 @@
         'idle',
         'ready',
         'sleeping',
-        'unknown',
-        'invalid',
       ]),
     }),
     'config_entry_id': <ANY>,
@@ -7279,8 +7269,6 @@
         'idle',
         'ready',
         'sleeping',
-        'unknown',
-        'invalid',
       ]),
     }),
     'context': <ANY>,
@@ -7949,8 +7937,6 @@
         'idle',
         'ready',
         'sleeping',
-        'unknown',
-        'invalid',
       ]),
     }),
     'config_entry_id': <ANY>,
@@ -7994,8 +7980,6 @@
         'idle',
         'ready',
         'sleeping',
-        'unknown',
-        'invalid',
       ]),
     }),
     'context': <ANY>,