diff --git a/setup.py b/setup.py
index b653f97..ddf628e 100644
--- a/setup.py
+++ b/setup.py
@@ -10,7 +10,7 @@
 
 requires = [
     'pyramid',
-    'pairtree',
+    'pairtree==0.7.1-T',
     'python-magic',
     'pyramid_rewrite'
     ]