backport r67325: make FileIO.mode always contain 'b'
diff --git a/Misc/NEWS b/Misc/NEWS
index d691d8c..c3f0ec6 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -56,6 +56,8 @@
 - Issue #4363: The uuid.uuid1() and uuid.uuid4() functions now work even if
   the ctypes module is not present.
 
+- FileIO's mode attribute now always includes ``"b"``.
+
 - Issue #4116: Resolve member name conflict in ScrolledCanvas.__init__.
 
 - httplib.HTTPConnection.putheader() now accepts an arbitrary number of values