diff --git a/questionnaire/emails.py b/questionnaire/emails.py
index c4173cc..b1f7f92 100644
--- a/questionnaire/emails.py
+++ b/questionnaire/emails.py
@@ -13,7 +13,7 @@ from django.template import loader
 from django.utils import translation
 from django.conf import settings
 from django.http import Http404, HttpResponse
-from django.shortcuts import render_to_response, get_object_or_404
+from django.shortcuts import get_object_or_404
 from .models import Subject, QuestionSet, RunInfo, Questionnaire
 
 try: from hashlib import md5
diff --git a/questionnaire/request_cache.py b/questionnaire/request_cache.py
index d9330cb..95c6134 100644
--- a/questionnaire/request_cache.py
+++ b/questionnaire/request_cache.py
@@ -9,6 +9,13 @@ from functools import wraps
 from threading import currentThread
 from django.core.cache.backends.locmem import LocMemCache
 
+try:
+    from django.utils.deprecation import MiddlewareMixin
+except ImportError:
+    # djang0 < 1.10
+    class MiddlewareMixin(object):
+        pass
+
 _request_cache = {}
 _installed_middleware = False
 
@@ -25,7 +32,7 @@ class RequestCache(LocMemCache):
         params = dict()
         super(RequestCache, self).__init__(name, params)
 
-class RequestCacheMiddleware(object):
+class RequestCacheMiddleware(MiddlewareMixin):
     def __init__(self):
         global _installed_middleware
         _installed_middleware = True