diff --git a/Gemfile.lock b/Gemfile.lock
index 2687e0a2fb..cfbd02aad0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -205,9 +205,9 @@ GEM
     sassc (2.4.0)
       ffi (~> 1.9)
     servolux (0.13.0)
-    sprockets (3.7.2)
+    sprockets (4.2.1)
       concurrent-ruby (~> 1.0)
-      rack (> 1, < 3)
+      rack (>= 2.2.4, < 4)
     temple (0.10.3)
     thor (0.20.3)
     tilt (2.0.11)