diff --git a/Gemfile b/Gemfile
index 82f9ff8..7cc736d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,7 +2,7 @@
 # the following line to use "https"
 source 'http://rubygems.org'
 
-gem "middleman", "~>3.1.3"
+gem "middleman", "~> 4.3.8"
 
 # Live-reloading plugin
 gem "middleman-livereload", "~> 3.1.0"