diff --git a/Gemfile b/Gemfile
index d09a386e..a374440a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
 gem 'rexml', '3.2.6'
-gem 'asciidoctor'
+gem 'asciidoctor', '2.0.22'
 gem 'asciidoctor-pdf'
 gem 'rouge', '3.30.0'