diff --git a/Gemfile b/Gemfile
index d7bd91223..ebfa881fe 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,7 +7,7 @@ gem 'json'
 gem 'awesome_print'
 
 gem 'asciidoctor-epub3', '1.0.0.alpha.2'
-gem 'asciidoctor-pdf', '1.5.0.alpha.5'
+gem 'asciidoctor-pdf', '1.5.0.alpha.12'
 
 gem 'coderay'
 gem 'pygments.rb'