diff --git a/sensu-plugins-ftp.gemspec b/sensu-plugins-ftp.gemspec
index 7ce586b..d7a62d5 100644
--- a/sensu-plugins-ftp.gemspec
+++ b/sensu-plugins-ftp.gemspec
@@ -34,7 +34,7 @@ Gem::Specification.new do |s|
 
   s.add_development_dependency 'bundler',                   '~> 1.7'
   s.add_development_dependency 'codeclimate-test-reporter', '~> 1.0'
-  s.add_development_dependency 'github-markup',             '~> 3.0'
+  s.add_development_dependency 'github-markup',             '~> 4.0'
   s.add_development_dependency 'pry',                       '~> 0.10'
   s.add_development_dependency 'rubocop',                   '~> 0.40.0'
   s.add_development_dependency 'rspec',                     '~> 3.1'