diff --git a/.github/workflows/regression.yml b/.github/workflows/regression.yml
index eb82a89c2..7dfde2755 100644
--- a/.github/workflows/regression.yml
+++ b/.github/workflows/regression.yml
@@ -15,14 +15,25 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       fail-fast: false
+      matrix:
+        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', '3.11']
+    # 3.12 does not yet work because numpy removed numpy.distutils that pygacode relies on
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v5
       with:
-        python-version: '3.6'
+        python-version: ${{ matrix.python-version }}
+        cache: 'pip'
+
+
+    - name: Extra dependencies required for 3.7
+      if: ${{matrix.python-version == '3.7'}}
+      run: |
+        sudo apt-get update
+        sudo apt-get install libhdf5-dev libnetcdf-dev
 
     - name: Install numpy
       run: |
@@ -32,7 +43,18 @@ jobs:
       run: |
         python3 -m pip install -r requirements.txt
 
-    - name: Install OMAS
+    # numpy is a build time dependency of pygacode
+    # but before pygacode 1.0 it did not specify its build dependencies correctly
+    # and pygacode requires python >= 3.8,
+    # so for 3.7 we need to build without build isolation and manually install numpy
+    - name: Install OMAS (Py 3.7)
+      if: ${{matrix.python-version == '3.7'}}
+      run: |
+        python3 -m pip install wheel
+        python3 -m pip install --no-build-isolation .[machine]
+
+    - name: Install OMAS (normal)
+      if: ${{matrix.python-version != '3.7'}}
       run: |
         python3 -m pip install .[machine]
 
diff --git a/omas/omas_plot.py b/omas/omas_plot.py
index bba21fa19..9b35ff38a 100644
--- a/omas/omas_plot.py
+++ b/omas/omas_plot.py
@@ -800,7 +800,7 @@ def get2d(contour_quantity):
             z = scipy.ndimage.zoom(z, sf)
             value_2d = scipy.ndimage.zoom(value_2d, sf)
 
-        cs = ax.contour(r, z, value_2d, levels, **kw)
+        cs = ax.contour(r, z, value_2d, levels=levels, **kw)
 
         if label_contours or ((label_contours is None) and (contour_quantity == 'q')):
             ax.clabel(cs)
diff --git a/omas/tests/failed_imports.py b/omas/tests/failed_imports.py
index 53fbf9782..f3b72c0a6 100644
--- a/omas/tests/failed_imports.py
+++ b/omas/tests/failed_imports.py
@@ -69,6 +69,8 @@
         failed_OMFIT = False
     except ImportError as _excp:
         failed_OMFIT = _excp
+    except AttributeError as _excp:
+        failed_OMFIT = "omfit_classes, from xarray import * bug "
 
 try:
     import MDSplus
diff --git a/omas/tests/test_omas_examples.py b/omas/tests/test_omas_examples.py
index 78b090530..f6c881e31 100644
--- a/omas/tests/test_omas_examples.py
+++ b/omas/tests/test_omas_examples.py
@@ -97,6 +97,12 @@ def test_uncertain(self):
 
     @unittest.skipIf(failed_OMFIT, str(failed_OMFIT))
     def test_plot_g_s_2_ip(self):
+        # on 3.7 this test raises:
+        # ValueError: Number of rows must be a positive integer, not 7.0
+        # It seems like this is caused by a bug in omfit_classes where a float
+        # instead of int is passed to plot
+        if sys.version_info.minor==7:
+            raise unittest.SkipTest("Avoid Py 3.7 omfit_classes bug.")
         from omas.examples import plot_g_s_2_ip
 
     def test_plot_saveload_scaling(self):
diff --git a/requirements.txt b/requirements.txt
index 5c5e3cfd4..d5a4b857b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,21 +2,22 @@
 #
 # usage: pip install -r requirements.txt
 
-numpy>=1.16.1            # required
-uncertainties            # required
-pint                     # required
-netCDF4                  # required
-boto3                    # required
-matplotlib               # required
-scipy                    # required
-h5py                     # required
-pymongo                  # required
-dnspython                # required
-xmltodict                # required
-xarray                   # required
-setuptools>=41.2         # required
-tqdm                     # required
-Cython                   # required
+numpy>=1.16.1                                      # required
+uncertainties                                      # required
+pint                                               # required
+netCDF4                                            # required
+boto3                                              # required
+matplotlib                                         # required
+scipy                                              # required
+h5py                                               # required
+pymongo                                            # required
+dnspython                                          # required
+xmltodict                                          # required
+xarray                                             # required
+setuptools>=41.2                                   # required
+tqdm                                               # required
+Cython                                             # required
+importlib_metadata <5;python_version=='3.7'        # required
 
 # omfit_classes            # machine
 # pexpect                  # machine
diff --git a/setup.py b/setup.py
index 5552fc857..0b7c5c4db 100644
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,4 @@
 import os
-import sys
 import glob
 import subprocess
 
@@ -19,6 +18,9 @@
     'setuptools>=41.2',
     'tqdm',
     'Cython',
+    # latest xarray version that works with 3.7 doesn't work
+    # with importlib_metadata >5 since they deprecated the `get()` method on Entrypoints
+    "importlib_metadata <5;python_version=='3.7'"
 ]
 
 extras_require = {
@@ -44,7 +46,7 @@
         f.write('# Do not edit this file by hand, operate on setup.py instead\n#\n')
         f.write('# usage: pip install -r requirements.txt\n\n')
         for item in install_requires:
-            f.write(item.ljust(25) + '# required\n')
+            f.write(item.ljust(50) + ' # required\n')
         for requirement in extras_require:
             f.write('\n')
             for item in extras_require[requirement]: