1 files changed, 4 insertions, 0 deletions
diff --git a/Misc/NEWS b/Misc/NEWS
index 1f4d55c..299ed3c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,10 @@ Release date: tba
 Core and Builtins
 -----------------
 
+- Issue #25421: __sizeof__ methods of builtin types now use dynamic basic size.
+  This allows sys.getsize() to work correctly with their subclasses with
+  __slots__ defined.
+
 - Issue #25709: Fixed problem with in-place string concatenation and utf-8 cache.
 
 - Issue #24097: Fixed crash in object.__reduce__() if slot name is freed inside