diff --git a/optuna_dashboard/_app.py b/optuna_dashboard/_app.py
index 8d9c366f..9a2a514e 100644
--- a/optuna_dashboard/_app.py
+++ b/optuna_dashboard/_app.py
@@ -249,11 +249,6 @@ def create_app(storage: BaseStorage, debug: bool = False) -> Bottle:
             return {"reason": "You need to set study_name and direction"}
 
         try:
-            # if version.parse(optuna_ver) >= version.Version("3.0.0rc0.dev"):
-            #         frozen_studies = storage.get_all_studies()  # type: ignore
-            #         return [_frozen_study_to_study_summary(s) for s in frozen_studies]
-            #     elif version.parse(optuna_ver) >= version.Version("3.0.0b0.dev"):
-            #         return storage.get_all_study_summaries(include_best_trial=False)  # type: ignore
             if version.parse(optuna_ver) >= version.Version("3.1.0.dev"):
                 study_id = storage.create_new_study(
                     study_name,
diff --git a/python_tests/test_api.py b/python_tests/test_api.py
index ead1ffc0..0bc8ee9f 100644
--- a/python_tests/test_api.py
+++ b/python_tests/test_api.py
@@ -2,9 +2,11 @@ import json
 from unittest import TestCase
 
 import optuna
-from optuna.study import StudyDirection
 from optuna import get_all_study_summaries
+from optuna.study import StudyDirection
+from optuna.version import __version__ as optuna_ver
 from optuna_dashboard._app import create_app
+from packaging import version
 
 from .wsgi_client import send_request
 
@@ -17,8 +19,13 @@ def objective(trial: optuna.trial.Trial) -> float:
 class APITestCase(TestCase):
     def test_get_study_summaries(self) -> None:
         storage = optuna.storages.InMemoryStorage()
-        storage.create_new_study(study_name="foo1", directions=[StudyDirection.MINIMIZE])
-        storage.create_new_study(study_name="foo2", directions=[StudyDirection.MINIMIZE])
+
+        if version.parse(optuna_ver) >= version.Version("3.1.0.dev"):
+            storage.create_new_study(study_name="foo1", directions=[StudyDirection.MINIMIZE])
+            storage.create_new_study(study_name="foo2", directions=[StudyDirection.MINIMIZE])
+        else:
+            storage.create_new_study("foo1")
+            storage.create_new_study("foo2")
 
         app = create_app(storage)
         status, _, body = send_request(
@@ -127,7 +134,10 @@ class APITestCase(TestCase):
 
     def test_create_study_duplicated(self) -> None:
         storage = optuna.storages.InMemoryStorage()
-        storage.create_new_study(study_name="foo", directions=[StudyDirection.MINIMIZE])
+        if version.parse(optuna_ver) >= version.Version("3.1.0.dev"):
+            storage.create_new_study(study_name="foo", directions=[StudyDirection.MINIMIZE])
+        else:
+            storage.create_new_study("foo")
         self.assertEqual(len(get_all_study_summaries(storage)), 1)
 
         app = create_app(storage)
@@ -147,8 +157,12 @@ class APITestCase(TestCase):
 
     def test_delete_study(self) -> None:
         storage = optuna.storages.InMemoryStorage()
-        storage.create_new_study(study_name="foo1", directions=[StudyDirection.MINIMIZE])
-        storage.create_new_study(study_name="foo2", directions=[StudyDirection.MINIMIZE])
+        if version.parse(optuna_ver) >= version.Version("3.1.0.dev"):
+            storage.create_new_study(study_name="foo1", directions=[StudyDirection.MINIMIZE])
+            storage.create_new_study(study_name="foo2", directions=[StudyDirection.MINIMIZE])
+        else:
+            storage.create_new_study(study_name="foo1")
+            storage.create_new_study(study_name="foo2")
         self.assertEqual(len(get_all_study_summaries(storage)), 2)
 
         app = create_app(storage)