diff --git a/examples/simple-jsbeautifyrc/test5.less b/examples/simple-jsbeautifyrc/test5.less
new file mode 100644
index 000000000..14bbf87de
--- /dev/null
+++ b/examples/simple-jsbeautifyrc/test5.less
@@ -0,0 +1,9 @@
+.animal {
+  color: red;
+}
+.dog {
+  &:extend(.animal);
+  &:hover {
+    color: green;
+  }
+}
diff --git a/package.json b/package.json
index 487653be9..9ebcf2967 100644
--- a/package.json
+++ b/package.json
@@ -90,7 +90,7 @@
     "strip-json-comments": "^0.1.3",
     "js-yaml": "^3.0.2",
     "temp": "^0.8.0",
-    "prettydiff": "^1.2.4",
+    "prettydiff": "^1.6.11",
     "node-uuid": "^1.4.1",
     "analytics-node": "^1.0.2",
     "coffee-formatter": "^0.1.0",