diff --git a/docs/Gemfile b/docs/Gemfile
index 053c27d..dadd74d 100644
--- a/docs/Gemfile
+++ b/docs/Gemfile
@@ -1,2 +1,2 @@
 source 'https://rubygems.org'
-gem 'github-pages'
+gem 'github-pages', '>= 224'