diff --git a/pyproject.toml b/pyproject.toml
index 22775cc9f0..ffc359a571 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,3 +1,6 @@
+[project]
+requires-python = "~=3.11.6"
+
 [tool.towncrier]
 package = "ai.backend.manager"  # reference point for getting __version__
 filename = "CHANGELOG.md"
diff --git a/src/ai/backend/client/cli/session/lifecycle.py b/src/ai/backend/client/cli/session/lifecycle.py
index a181a2b26c..e73918ff73 100644
--- a/src/ai/backend/client/cli/session/lifecycle.py
+++ b/src/ai/backend/client/cli/session/lifecycle.py
@@ -8,6 +8,7 @@
 import uuid
 from collections import OrderedDict, defaultdict
 from datetime import datetime, timedelta
+from graphlib import TopologicalSorter
 from pathlib import Path
 from typing import IO, List, Literal, Optional, Sequence
 
@@ -18,7 +19,6 @@
 from dateutil.parser import isoparse
 from dateutil.tz import tzutc
 from faker import Faker
-from graphlib import TopologicalSorter
 from humanize import naturalsize
 from tabulate import tabulate