diff --git a/Gemfile b/Gemfile
index 4fc585d..4120b92 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,4 +1,4 @@
 source :rubygems
 
-gem "middleman", "~>3.0.2"
+gem "middleman", "~> 4.0.0"
 gem "middleman-sync", "~> 3.0.5"