diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2dfdfab75f84aff905ec88f7f8b4bb442bff093c..3409c3383e70766116c07d1cc21dfe0baf0ce838 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -16,11 +16,12 @@ minimal-windows:
   tags:
     - i10swarm11
   script:
-    - source /cygdrive/c/Users/build/Miniconda3/Scripts/activate
-    - source activate pystencils_dev
-    - env
-    - conda env list
+    - echo $0
+    - /cygdrive/c/Users/build/Miniconda3/Scripts/conda activate pystencils_dev
+    - /cygdrive/c/Users/build/Miniconda3/Scripts/conda env list
+    - grep sympy setup.py
+    - grep -Eo 'sympy[>=]+[0-9\.]+' setup.py | sed 's/>/=/g'
+    - conda update sympy==1.2
     - pip install git+https://gitlab-ci-token:${CI_JOB_TOKEN}@i10git.cs.fau.de/pycodegen/pystencils.git@master#egg=pystencils
     - python -c "import numpy"
     - python setup.py quicktest
-