diff --git a/tools/oldest_constraints.txt b/tools/oldest_constraints.txt
index 1f415dd4c..5d1446005 100644
--- a/tools/oldest_constraints.txt
+++ b/tools/oldest_constraints.txt
@@ -60,6 +60,7 @@ distro==1.0.1
 # Lexicon oldest constraint is overridden appropriately on relevant DNS provider plugins
 # using their local-oldest-requirements.txt
 dns-lexicon==2.2.1
+httplib2==0.9.2
 
 # Plugin constraints
 # These aren't necessarily the oldest versions we need to support