diff --git a/docs/conf.py b/docs/conf.py
index 8bb2bf953..09daf8877 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -120,7 +120,6 @@
     "enquiries": default_extension_version,
     "location": default_extension_version,
     "lots": default_extension_version,
-    "milestone_documents": default_extension_version,
     "participation_fee": default_extension_version,
     "process_title": default_extension_version,
 }