diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 118c4818..947e43d5 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -10,7 +10,7 @@ jobs:
     timeout-minutes: 60
     strategy:
       matrix:
-        python-version: ["3.10", "3.11"]
+        python-version: ["3.10"]
     services:
       rabbitmq:
         image: "rabbitmq:3.9"
diff --git a/alab_management/resource_manager/resource_requester.py b/alab_management/resource_manager/resource_requester.py
index c996b117..ff549a80 100644
--- a/alab_management/resource_manager/resource_requester.py
+++ b/alab_management/resource_manager/resource_requester.py
@@ -34,18 +34,12 @@ class RequestCanceledError(Exception):
     """Request Canceled Error."""
 
 
-# considering concurrent.futures.TimeoutError and TimeoutError becomes the same
-# from Python 3.11. We should determine the base class of this exception.
-if isinstance(concurrent.futures.TimeoutError, TimeoutError):
-    CombinedTimeoutError = TimeoutError
-else:
-
-    class CombinedTimeoutError(TimeoutError, concurrent.futures.TimeoutError):
-        """
-        Combined TimeoutError.
+class CombinedTimeoutError(TimeoutError, concurrent.futures.TimeoutError):
+    """
+    Combined TimeoutError.
 
-        If you catch either TimeoutError or concurrent.futures.TimeoutError, this will catch both.
-        """
+    If you catch either TimeoutError or concurrent.futures.TimeoutError, this will catch both.
+    """
 
 
 class DeviceRequest(BaseModel):