diff --git a/pyproject.toml b/pyproject.toml
index d32d3af10..758208691 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -223,7 +223,7 @@ disable = ["R0801"]
 extend-exclude = ["tests/profiles/syntax_error.py"]
 
 [tool.ruff.lint]
-extend-select = ["TID251", "UP006", "UP007", "UP035", "RUF100"]
+extend-select = ["TID251", "UP006", "UP007", "UP017", "UP035", "RUF100"]
 
 [tool.ruff.lint.flake8-tidy-imports.banned-api]
 unittest = { msg = "use pytest instead of unittest" }
diff --git a/src/app/endpoints/a2a.py b/src/app/endpoints/a2a.py
index c09a857ee..a00ece91e 100644
--- a/src/app/endpoints/a2a.py
+++ b/src/app/endpoints/a2a.py
@@ -4,7 +4,7 @@
 import json
 import uuid
 from collections.abc import Mapping, AsyncIterator, MutableMapping
-from datetime import datetime, timezone
+from datetime import datetime, UTC
 from typing import Annotated, Any, Optional
 
 from a2a.server.agent_execution import AgentExecutor, RequestContext
@@ -381,7 +381,7 @@ async def _process_task_streaming(  # pylint: disable=too-many-locals
                 task_id=task_id,
                 status=TaskStatus(
                     state=TaskState.working,
-                    timestamp=datetime.now(timezone.utc).isoformat(),
+                    timestamp=datetime.now(UTC).isoformat(),
                 ),
                 context_id=context_id,
                 final=False,
@@ -403,14 +403,14 @@ async def _process_task_streaming(  # pylint: disable=too-many-locals
         if aggregator.task_state == TaskState.working:
             await task_updater.update_status(
                 TaskState.completed,
-                timestamp=datetime.now(timezone.utc).isoformat(),
+                timestamp=datetime.now(UTC).isoformat(),
                 final=True,
             )
         else:
             await task_updater.update_status(
                 aggregator.task_state,
                 message=aggregator.task_status_message,
-                timestamp=datetime.now(timezone.utc).isoformat(),
+                timestamp=datetime.now(UTC).isoformat(),
                 final=True,
             )
 
@@ -459,7 +459,7 @@ async def _convert_stream_to_events(  # pylint: disable=too-many-branches,too-ma
                                 context_id=context_id,
                                 task_id=task_id,
                             ),
-                            timestamp=datetime.now(timezone.utc).isoformat(),
+                            timestamp=datetime.now(UTC).isoformat(),
                         ),
                         context_id=context_id,
                         final=False,
@@ -477,7 +477,7 @@ async def _convert_stream_to_events(  # pylint: disable=too-many-branches,too-ma
                             context_id=context_id,
                             task_id=task_id,
                         ),
-                        timestamp=datetime.now(timezone.utc).isoformat(),
+                        timestamp=datetime.now(UTC).isoformat(),
                     ),
                     context_id=context_id,
                     final=False,
@@ -495,7 +495,7 @@ async def _convert_stream_to_events(  # pylint: disable=too-many-branches,too-ma
                             context_id=context_id,
                             task_id=task_id,
                         ),
-                        timestamp=datetime.now(timezone.utc).isoformat(),
+                        timestamp=datetime.now(UTC).isoformat(),
                     ),
                     context_id=context_id,
                     final=False,
@@ -891,5 +891,5 @@ async def a2a_health_check() -> dict[str, str]:
         "service": "lightspeed-a2a",
         "version": __version__,
         "a2a_sdk_version": "0.3.4",
-        "timestamp": datetime.now(timezone.utc).isoformat(),
+        "timestamp": datetime.now(UTC).isoformat(),
     }
diff --git a/src/app/endpoints/query.py b/src/app/endpoints/query.py
index 2a0f5faf4..fd123bd21 100644
--- a/src/app/endpoints/query.py
+++ b/src/app/endpoints/query.py
@@ -237,9 +237,7 @@ async def query_endpoint_handler(
         quota_limiters=configuration.quota_limiters, user_id=user_id
     )
 
-    completed_at = datetime.datetime.now(datetime.timezone.utc).strftime(
-        "%Y-%m-%dT%H:%M:%SZ"
-    )
+    completed_at = datetime.datetime.now(datetime.UTC).strftime("%Y-%m-%dT%H:%M:%SZ")
     conversation_id = normalize_conversation_id(responses_params.conversation)
 
     logger.info("Storing query results")
diff --git a/tests/unit/app/endpoints/test_conversations_v2.py b/tests/unit/app/endpoints/test_conversations_v2.py
index 8e8787809..0d1c76ab9 100644
--- a/tests/unit/app/endpoints/test_conversations_v2.py
+++ b/tests/unit/app/endpoints/test_conversations_v2.py
@@ -2,7 +2,7 @@
 
 """Unit tests for the /conversations REST API endpoints."""
 
-from datetime import datetime, timezone
+from datetime import datetime, UTC
 from typing import Any, cast
 
 import pytest
@@ -361,9 +361,7 @@ async def test_successful_retrieval(
         mocker.patch("app.endpoints.conversations_v2.configuration", mock_configuration)
 
         timestamp_str = "2024-01-01T00:00:00Z"
-        timestamp_dt = datetime.fromisoformat(timestamp_str).replace(
-            tzinfo=timezone.utc
-        )
+        timestamp_dt = datetime.fromisoformat(timestamp_str).replace(tzinfo=UTC)
         timestamp = timestamp_dt.timestamp()
 
         mock_configuration.conversation_cache.list.return_value = [