diff --git a/sphinx/domains/cpp.py b/sphinx/domains/cpp.py
index 5e239a2d9ea..311885e5dbe 100644
--- a/sphinx/domains/cpp.py
+++ b/sphinx/domains/cpp.py
@@ -8033,7 +8033,7 @@ def initStuff(app):
 
     return {
         'version': 'builtin',
-        'env_version': 4,
+        'env_version': 5,
         'parallel_read_safe': True,
         'parallel_write_safe': True,
     }