diff --git a/pyproject.toml b/pyproject.toml
index fe6b112f..ac4adb2b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -72,6 +72,12 @@ dev = [
     'nbsphinx>=0.5.0,<0.7',
     'Sphinx>=1.7.1,<3',
     'sphinx_rtd_theme>=0.2.4,<0.5',
+    'sphinxcontrib_applehelp<1.0.8',
+    'sphinxcontrib-devhelp<1.0.6',
+    'sphinxcontrib-htmlhelp<2.0.5',
+    'sphinxcontrib_serializinghtml<1.1.10',
+    'sphinxcontrib_qthelp<1.0.7',
+    'alabaster<0.7.13',
 
     # Jinja2>=3 makes the sphinx theme fail
     'Jinja2>=2,<3',