diff --git a/.ruby-version b/.ruby-version
index 2bf1c1c..197c4d5 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.3.1
+2.4.0
diff --git a/Gemfile b/Gemfile
index 115ed7e..ff96820 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source "https://rubygems.org"
 
-ruby "2.3.1"
+ruby "2.4.0"
 
 gem "accesslint-ci", "0.2.8"
 gem "bourbon", "~> 5.0.0.beta.7"