diff --git a/django/forms/util.py b/django/forms/util.py
index 0a73320f83..3c7724900a 100644
--- a/django/forms/util.py
+++ b/django/forms/util.py
@@ -1,5 +1,7 @@
 from __future__ import unicode_literals
 
+import warnings
+
 from django.conf import settings
 from django.utils.html import format_html, format_html_join
 from django.utils.encoding import force_text, python_2_unicode_compatible
@@ -21,6 +23,11 @@ def flatatt(attrs):
 
     The result is passed through 'mark_safe'.
     """
+    if [v for v in attrs.values() if v is True or v is False]:
+        warnings.warn(
+            'The meaning of boolean values for widget attributes will change in Django 1.8',
+            DeprecationWarning
+        )
     return format_html_join('', ' {0}="{1}"', sorted(attrs.items()))
 
 @python_2_unicode_compatible