diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f5b3e9b..f53401d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -26,20 +26,20 @@ jobs:
             python-version: 3.9
             toxenv: py39
 
-          - name: Python 3.8
+          - name: Python 3.12
             runs-on: ubuntu-latest
-            python-version: 3.8
-            toxenv: py38
+            python-version: 3.12
+            toxenv: py312
 
           - name: Code style checks
             runs-on: ubuntu-latest
-            python-version: 3.8
+            python-version: 3.11
             toxenv: style
 
-          - name: Python 3.8 with dev dependencies
+          - name: Python 3.11 with dev dependencies
             runs-on: ubuntu-latest
-            python-version: 3.8
-            toxenv: py38-dev
+            python-version: 3.11
+            toxenv: py311-dev
     steps:
       - uses: actions/checkout@v2
         with:
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 37adcf6..f69e6b1 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,2 +1,6 @@
-git+https://github.com/astropy/astropy.git
 git+https://github.com/spacetelescope/stsci.tools.git
+--extra-index-url https://pypi.anaconda.org/astropy/simple astropy --pre
+
+# Use Bi-weekly numpy/scipy dev builds
+--extra-index-url https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
+numpy>=0.0.dev0
diff --git a/setup.cfg b/setup.cfg
index 29ad907..e6f9d08 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -9,7 +9,7 @@ edit_on_github = False
 github_project = spacetelescope/stwcs
 
 [tool:pytest]
-minversion = 3.6
+minversion = 3.9
 norecursedirs = build docs/_build relic
 filterwarnings=
   ignore:.*Card is too long*
diff --git a/setup.py b/setup.py
index 00c47db..e16656d 100755
--- a/setup.py
+++ b/setup.py
@@ -3,11 +3,6 @@
 from setuptools import setup, find_packages
 from configparser import ConfigParser
 
-if sys.version_info < (3, 6):
-    error = """
-    STWCS supports Python 3.6 and above.
-    """
-    sys.exit(error)
 
 conf = ConfigParser()
 conf.read(['setup.cfg'])
diff --git a/tox.ini b/tox.ini
index d7dd5a5..fc33064 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist= py38, py310, style
+envlist= py311, py312, py310, style
 
 [testenv]
 deps=