diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e7ed515..99c2eb2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,10 +3,10 @@ name: CI
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
     branches:
-      - master
+      - main
   workflow_dispatch:
 
 jobs:
@@ -15,12 +15,12 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest]
-        python: [3.6, 3.9]
+        os: ["ubuntu-20.04"]
+        python: [3.6, 3.9, 3.11]
     steps:
       - uses: actions/checkout@v2
       - name: Setup Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: ${{ matrix.python }}
       - name: Install tox
diff --git a/paddles/tests/controllers/test_nodes.py b/paddles/tests/controllers/test_nodes.py
index fdfb5e0..c17498d 100644
--- a/paddles/tests/controllers/test_nodes.py
+++ b/paddles/tests/controllers/test_nodes.py
@@ -1,5 +1,3 @@
-import pytest
-
 from paddles.tests import TestApp
 from paddles.models import Node, Job, start, commit
 
@@ -317,7 +315,6 @@ def test_update(self):
 
     def test_delete(self):
         node_name = 'a_node'
-        user = 'a_user'
         self.app.post_json('/nodes/', dict(name=node_name))
         response = self.app.get('/nodes/{name}/'.format(name=node_name))
         assert response.json['name'] == node_name
diff --git a/requirements.txt b/requirements.txt
index 32c084c..6bfc43d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,13 +2,13 @@ alembic==0.8.2
 Mako==1.0.2
 mccabe==0.3.1
 pecan==1.3.3
-psycopg2-binary==2.8.6
-pytz==2015.6
+psycopg2-binary==2.9.5
+pytz==2023.3
 requests==2.20.0
 simplegeneric==0.8.1
 SQLAlchemy==1.3.0
 tzlocal==1.2
-WebTest==2.0.18
+WebTest==3.0.0
 gunicorn==20.0.4
 python-statsd==2.0.0
 mock==2.0.0