diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f4d042f003042319b3867857b756665a2aa3ddfc..eacbe3e26323e0a0bf1579cba53e2e12ecfd27c0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -42,7 +42,7 @@ tests (from scratch):
     - ./CI/update_badge.sh > /dev/null
   script:
     - pip install --upgrade pip
-    - pip install numpy wheel six
+    - pip install numpy wheel six==1.15.0
     - zypper --non-interactive install binutils libproj-devel gdal-devel
     - zypper --non-interactive install proj geos-devel
     #    - cat requirements.txt | cut -f1 -d"#" | sed '/^\s*$/d' | xargs -L 1 pip install
diff --git a/requirements.txt b/requirements.txt
index c4b281bbc030551650b76def4e072773df136d78..b0a6e7f59896fd0edf08977ee553c803f6c2e960 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -51,7 +51,7 @@ PyYAML==5.4.1
 requests==2.25.1
 scipy==1.5.4
 seaborn==0.11.1
---ignore-installed six==1.15.0
+six==1.15.0
 statsmodels==0.12.2
 tabulate==0.8.8
 tensorboard==1.13.1