Patch #1623563: allow __class__ assignment for classes with __slots__.
The old and the new class are still required to have the same slot
names, but the order in which they are specified is not relevant.
diff --git a/Misc/NEWS b/Misc/NEWS
index 8af1eb1..6e336b6 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
 Core and builtins
 -----------------
 
+- Patch #1623563: allow __class__ assignment for classes with __slots__.
+  The old and the new class are still required to have the same slot names.
+
 - Patch #1642547: Fix an error/crash when encountering syntax errors in
   complex if statements.