Add news about changes to metaclasses and __bases__ error checking.
diff --git a/Misc/NEWS b/Misc/NEWS
index c60cf39..4ef206a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -126,6 +126,13 @@
- Bug #1664966: Fix crash in exec if Unicode filename can't be decoded.
+- Add new requirements for metaclasses. 1) If type or a subclass of type
+ occurs in __bases__, it must occur before any non-type bases, e.g.
+ before regular classes. 2) If you assign to __bases__, you may not
+ change the metaclass. Many more illegal assignments to __bases__
+ are now checked and raise TypeErrors. This changed fixed at least
+ one known crash.
+
Library
-------