diff --git a/documentation/conf.py b/documentation/conf.py
index 407ea3292f..5a2e25f7b2 100644
--- a/documentation/conf.py
+++ b/documentation/conf.py
@@ -33,6 +33,9 @@ author = 'The Linux Foundation'
 
 # -- General configuration ---------------------------------------------------
 
+# Prevent building with an outdated version of sphinx
+needs_sphinx = "3.1"
+
 # to load local extension from the folder 'sphinx'
 sys.path.insert(0, os.path.abspath('sphinx'))