diff --git a/utility.ptree b/utility.ptree
index 809b9b9..0656210 100644
--- a/utility.ptree
+++ b/utility.ptree
@@ -1,5 +1,5 @@
 #lang pollen
-◊(require sugar/coerce sugar/string sugar/file)
+◊(require sugar/coerce sugar/unstable/string sugar/file)
 
 error.html