diff --git a/tox.ini b/tox.ini
index ae2ef9e07..cf0188e3b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,6 +13,7 @@ deps =
     boto
     Pillow
     leveldb
+    service_identity
     -rtests/requirements.txt
 commands =
     py.test {posargs:scrapy tests}
@@ -39,14 +40,14 @@ commands =
 [testenv:py33]
 basepython = python3.3
 deps =
-;    svn+svn://svn.twistedmatrix.com/svn/Twisted/trunk#egg=Twisted
-    Twisted >= 14.0.0
+    Twisted >= 15.1.0
     lxml>=3.2.4
     pyOpenSSL>=0.13.1
     cssselect>=0.9
     queuelib>=1.1.1
     w3lib>=1.8.0
     Pillow
+    service_identity
     # tests requirements
     pytest>=2.6.0
     pytest-twisted