diff --git a/pyoverkiz/enums/execution.py b/pyoverkiz/enums/execution.py
index 073224e5..f5feb482 100644
--- a/pyoverkiz/enums/execution.py
+++ b/pyoverkiz/enums/execution.py
@@ -1,8 +1,12 @@
+import logging
 from enum import Enum, unique
 
+_LOGGER = logging.getLogger(__name__)
+
 
 @unique
 class ExecutionType(str, Enum):
+    UNKNOWN = "UNKNOWN"
     IMMEDIATE_EXECUTION = "Immediate execution"
     DELAYED_EXECUTION = "Delayed execution"
     TECHNICAL_EXECUTION = "Technical execution"
@@ -10,9 +14,15 @@ class ExecutionType(str, Enum):
     RAW_TRIGGER_SERVER = "Raw trigger (Server)"
     RAW_TRIGGER_GATEWAY = "Raw trigger (Gateway)"
 
+    @classmethod
+    def _missing_(cls, value):  # type: ignore
+        _LOGGER.warning(f"Unsupported value {value} has been returned for {cls}")
+        return cls.UNKNOWN
+
 
 @unique
 class ExecutionState(str, Enum):
+    UNKNOWN = "UNKNOWN"
     INITIALIZED = "INITIALIZED"
     NOT_TRANSMITTED = "NOT_TRANSMITTED"
     TRANSMITTED = "TRANSMITTED"
@@ -22,9 +32,16 @@ class ExecutionState(str, Enum):
     QUEUED_GATEWAY_SIDE = "QUEUED_GATEWAY_SIDE"
     QUEUED_SERVER_SIDE = "QUEUED_SERVER_SIDE"
 
+    @classmethod
+    def _missing_(cls, value):  # type: ignore
+        _LOGGER.warning(f"Unsupported value {value} has been returned for {cls}")
+        return cls.UNKNOWN
+
 
 @unique
 class ExecutionSubType(str, Enum):
+    UNKNOWN = "UNKNOWN"
+    _ = "-"
     ACTION_GROUP = "ACTION_GROUP"
     ACTION_GROUP_SEQUENCE = "ACTION_GROUP_SEQUENCE"
     DAWN_TRIGGER = "DAWN_TRIGGER"
@@ -37,3 +54,8 @@ class ExecutionSubType(str, Enum):
     NO_ERROR = "NO_ERROR"
     P2P_COMMAND_REGULATION = "P2P_COMMAND_REGULATION"
     TIME_TRIGGER = "TIME_TRIGGER"
+
+    @classmethod
+    def _missing_(cls, value):  # type: ignore
+        _LOGGER.warning(f"Unsupported value {value} has been returned for {cls}")
+        return cls.UNKNOWN
diff --git a/tests/test_enums.py b/tests/test_enums.py
index 4b73ea7d..c8f4499d 100644
--- a/tests/test_enums.py
+++ b/tests/test_enums.py
@@ -1,4 +1,11 @@
-from pyoverkiz.enums import EventName, FailureType, GatewaySubType, GatewayType
+from pyoverkiz.enums import (
+    EventName,
+    ExecutionSubType,
+    ExecutionType,
+    FailureType,
+    GatewaySubType,
+    GatewayType,
+)
 
 
 class TestGatewayType:
@@ -30,3 +37,13 @@ def test_missing(self):
 class TestFailureType:
     def test_missing(self):
         assert FailureType(99) == FailureType.UNKNOWN
+
+
+class TestExecutionType:
+    def test_missing(self):
+        assert ExecutionType("test") == ExecutionType.UNKNOWN
+
+
+class TestExecutionSubType:
+    def test_missing(self):
+        assert ExecutionSubType("test") == ExecutionSubType.UNKNOWN