diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index a756acb..c688ab5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -27,9 +27,10 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - {name: Linux, python: '3.12', os: ubuntu-latest, tox: py312}
-          - {name: Windows, python: '3.12', os: windows-latest, tox: py312}
-          - {name: Mac, python: '3.12', os: macos-latest, tox: py312}
+          - {name: Linux, python: '3.13', os: ubuntu-latest, tox: py313}
+          - {name: Windows, python: '3.13', os: windows-latest, tox: py313}
+          - {name: Mac, python: '3.13', os: macos-latest, tox: py313}
+          - {name: '3.12', python: '3.12', os: ubuntu-latest, tox: py312}
           - {name: '3.11', python: '3.11', os: ubuntu-latest, tox: py311}
           - {name: '3.10', python: '3.10', os: ubuntu-latest, tox: py310}
           - {name: Typing, python: '3.12', os: ubuntu-latest, tox: typing}
diff --git a/MAINTENANCE.md b/MAINTENANCE.md
index 1e47a2e..83459b8 100644
--- a/MAINTENANCE.md
+++ b/MAINTENANCE.md
@@ -2,7 +2,10 @@
 
 ## Note
 
-- GitHub Codespace now use Python 3.12. However, our school machines still have 3.10.
+### Why are we supporting Python 3.10 to 3.13?
+
+Our lab machines still using Python 3.10.x. GitHub Codespace should still be using Python 3.12.x.
+Student who want to run the grading script locally may download 3.13 from python.org website.
 
 ## First time setup
 
diff --git a/tox.ini b/tox.ini
index 0f2d31f..c69d238 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,7 +2,7 @@
 requires =
     tox>=4
 env_list =
-    py3{10,11,12}
+    py3{10,11,12,13}
     lint
     typing