diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 680b66c..22ee357 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -31,11 +31,8 @@ jobs:
         if: ${{ startsWith( matrix.os, 'ubuntu') && matrix.python-version == 3.12 }}
         run: |
           sudo apt-get install libhdf5-dev
-          python3 -m pip install --upgrade pip
-          python3 -m pip install git+https://github.com/PyTables/PyTables.git
       - name: Install SimWeights
         run: |
-          python3 -m pip install --upgrade pip
           python3 -m pip install flit
           python3 -m flit install --symlink --deps=production --extras=test
       - name: Download Test Data
diff --git a/pyproject.toml b/pyproject.toml
index f69b1ff..3ad93ab 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: BSD-2-Clause
 
 [build-system]
-requires = ["flit_core >=2,<4"]
+requires = ["flit_core >=3.2,<4"]
 build-backend = "flit_core.buildapi"
 
 [project]
@@ -24,6 +24,7 @@ classifiers = [
     'Programming Language :: Python :: 3.9',
     'Programming Language :: Python :: 3.10',
     'Programming Language :: Python :: 3.11',
+    'Programming Language :: Python :: 3.12',
     'Topic :: Scientific/Engineering :: Astronomy',
     'Topic :: Scientific/Engineering :: Physics',
     ]
@@ -31,7 +32,7 @@ dependencies = ["numpy>=1.21.2", "scipy"]
 dynamic = ["version", "description"]
 
 [project.optional-dependencies]
-test = [ "h5py", "tables", "pandas", "uproot", "pytest-cov"]
+test = ["h5py", "tables < 3.8; python_version < '3.9'", "tables", "pandas", "uproot", "pytest-cov"]
 docs = ["sphinx","sphinx-rtd-theme","pandas"]
 dev = ["pytest","pre-commit","reuse","black","ruff","pylint","mypy"]
 
diff --git a/tox.ini b/tox.ini
index d7c2ae4..6942f1a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,10 +3,10 @@
 ; SPDX-License-Identifier: BSD-2-Clause
 
 [tox]
-envlist = py3{7,8,9,10,11}
+envlist = py3{8,9,10,11,12}
 isolated_build = True
 
 [testenv]
-passenv = SIMWEIGHTS_TESTDATA
+passenv = SIMWEIGHTS_TESTDATA, HDF5_DIR
 deps = .[test]
 commands = pytest