diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 13ed62d5fd669ae821af74946491ceea9d9969d8..2819d3f760ff9dda6116289ef536ce7a7400bd82 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -61,7 +61,7 @@ test-centos7:
   - coverage run --source='.' manage.py test
   - coverage report
   - coverage html
-  - pip3.6 install sphinx==3.5.3 sphinx-argparse==0.2.5 sphinxcontrib.bibtex==2.1.4 sphinx_rtd_theme==0.5.1
+  - pip3.6 install sphinx==3.5.2 sphinx-argparse==0.2.5 sphinxcontrib.bibtex==2.1.4 sphinx_rtd_theme==0.5.1
   - cd docs
   - PYTHON=python3.6 make html
   artifacts:
diff --git a/ippisite/requirements-dev.txt b/ippisite/requirements-dev.txt
index d9e46e82dac8a42e3e362c1cea5c31e81e60bd81..1549db98da83318c76e564367834cb831570a3f1 100644
--- a/ippisite/requirements-dev.txt
+++ b/ippisite/requirements-dev.txt
@@ -4,9 +4,9 @@ flake8
 black
 flake8-black
 # documentation generation
-sphinx
-sphinx_rtd_theme
-sphinxcontrib-bibtex
+Sphinx==3.5.2
+sphinx_rtd_theme==0.5.1
+sphinxcontrib-bibtex==2.1.4
 # coverage
 coverage
 # tests