diff --git a/.github/workflows/run-tests-push.yml b/.github/workflows/run-tests-push.yml
index 7c1e5b8a..224c5ae9 100644
--- a/.github/workflows/run-tests-push.yml
+++ b/.github/workflows/run-tests-push.yml
@@ -19,7 +19,6 @@ jobs:
           environment-file: environment.yml
           python-version: ${{ matrix.python-version }}
           miniforge-version: "latest"
-          miniforge-variant: Mambaforge
           use-mamba: true
       - shell: bash -l {0}
         run: conda --version
diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 729588a7..7b6937df 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -24,7 +24,6 @@ jobs:
           environment-file: environment.yml
           python-version: ${{ matrix.python-version }}
           miniforge-version: "latest"
-          miniforge-variant: Mambaforge
           use-mamba: true
       - shell: bash -l {0}
         run: conda --version
diff --git a/environment.yml b/environment.yml
index 3a60e75c..f2998d47 100644
--- a/environment.yml
+++ b/environment.yml
@@ -11,7 +11,7 @@ dependencies:
   - matplotlib
   - nctoolkit >=0.8.7  # use linux64 build
   - netcdf4
-  - numpy >1.24.3 
+  - numpy >1.24.3,<2.0  # needs thorough checking when released
   - pip !=21.3
   - python >=3.9
   - pyyaml
diff --git a/setup.py b/setup.py
index 377b4674..3d385086 100755
--- a/setup.py
+++ b/setup.py
@@ -30,7 +30,7 @@
         'matplotlib',
         'nctoolkit>=0.8.7',  # use linux64 build
         'netcdf4',
-        'numpy>1.24.3',
+        'numpy>1.24.3,<2.0',
         'pip!=21.3',
         'pyyaml',
         'scikit-learn',