diff --git a/.github/workflows/ci_workflows.yml b/.github/workflows/ci_workflows.yml
index cc1d9fd..e77b51e 100644
--- a/.github/workflows/ci_workflows.yml
+++ b/.github/workflows/ci_workflows.yml
@@ -80,8 +80,8 @@ jobs:
 
           - name: Test with dev dependencies
             os: ubuntu-latest
-            python: '3.11'
-            toxenv: py311-test-devdeps
+            python: '3.12-dev'
+            toxenv: py312-test-devdeps
 
           - name: Test with old dependencies
             os: ubuntu-20.04
@@ -102,7 +102,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: Set up Python
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 89d6860..85a5501 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -37,7 +37,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
diff --git a/.github/workflows/predeps_workflow.yml b/.github/workflows/predeps_workflow.yml
index 4cc3a44..4a7492e 100644
--- a/.github/workflows/predeps_workflow.yml
+++ b/.github/workflows/predeps_workflow.yml
@@ -40,7 +40,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: Set up Python
diff --git a/.github/workflows/publish-to-pypi.yml b/.github/workflows/publish-to-pypi.yml
index b7c3d2f..6187a2a 100644
--- a/.github/workflows/publish-to-pypi.yml
+++ b/.github/workflows/publish-to-pypi.yml
@@ -16,7 +16,7 @@ jobs:
     if: github.repository == 'spacetelescope/stsynphot_refactor'
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
 
diff --git a/tox.ini b/tox.ini
index 4a162b7..63d406c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{39,310,311}-test{,-alldeps,-oldestdeps,-devdeps,-predeps}{,-cov}
+    py{39,310,311,312}-test{,-alldeps,-oldestdeps,-devdeps,-predeps}{,-cov}
     codestyle
     twine
     bandit