diff --git a/mkspecs/features/default_post.prf b/mkspecs/features/default_post.prf
index 18f8b8ad9a..b94aab3e9c 100644
--- a/mkspecs/features/default_post.prf
+++ b/mkspecs/features/default_post.prf
@@ -122,6 +122,7 @@ breakpad {
 }
 
 c++17: CONFIG += c++1z
+c++20: CONFIG += c++2a
 c++latest: CONFIG *= c++2a c++1z c++14 c++11
 
 !c++1z:!c++2a {