diff --git a/.github/workflows/cache.yml b/.github/workflows/cache.yml
index f25cb68be..c0a6078b4 100644
--- a/.github/workflows/cache.yml
+++ b/.github/workflows/cache.yml
@@ -15,7 +15,7 @@ jobs:
           auto-update-conda: true
           auto-activate-base: true
           miniconda-version: 'latest'
-          python-version: 3.8
+          python-version: 3.9
           environment-file: environment.yml
           activate-environment: quantecon
       - name: Install latex dependencies
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 718eecb7b..de506146f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
           auto-update-conda: true
           auto-activate-base: true
           miniconda-version: 'latest'
-          python-version: 3.8
+          python-version: 3.9
           environment-file: environment.yml
           activate-environment: quantecon
       - name: Install latex dependencies
diff --git a/.github/workflows/execution.yml b/.github/workflows/execution.yml
index 440cce434..f2bbe3db6 100644
--- a/.github/workflows/execution.yml
+++ b/.github/workflows/execution.yml
@@ -11,7 +11,7 @@ jobs:
       fail-fast: false
       matrix:
         os: ["ubuntu-latest"]
-        python-version: ["3.8"]
+        python-version: ["3.9"]
     steps:
       - name: Checkout
         uses: actions/checkout@v2
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index d12bf3fe3..3adcf6978 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -16,7 +16,7 @@ jobs:
           auto-update-conda: true
           auto-activate-base: true
           miniconda-version: 'latest'
-          python-version: 3.8
+          python-version: 3.9
           environment-file: environment.yml
           activate-environment: quantecon
       - name: Install latex dependencies
diff --git a/environment.yml b/environment.yml
index 88128d1f6..b1109c041 100644
--- a/environment.yml
+++ b/environment.yml
@@ -2,17 +2,23 @@ name: quantecon
 channels:
   - default
 dependencies:
-  - python=3.8
-  - anaconda=2021.11
+  - python=3.9
+  - anaconda=2022.05
   - pip
   - pip:
-    - jupyter-book==0.12.1
-    - quantecon-book-theme==0.3.0
-    - sphinx-tojupyter==0.2.0
+    - jupyter-book==0.12.3
+    - quantecon-book-theme==0.3.1
+    - sphinx-tojupyter==0.2.1
     - sphinxext-rediraffe==0.2.7
-    - sphinx-exercise==0.2.1
+    - sphinx-exercise==0.4.0
     - ghp-import==1.1.0
-    - sphinxcontrib-youtube
-    # Test
-    - numba==0.55.1
-
+    - sphinxcontrib-youtube==1.1.0
+    - sphinx-togglebutton==0.3.1
+    # Sandpit Requirements
+    - quantecon
+    - array-to-latex
+    - PuLP
+    - cvxpy
+    - cvxopt
+    - cylp
+    - prettytable