diff --git a/Gemfile b/Gemfile
index 7f7be01eb95..24aaecd9841 100644
--- a/Gemfile
+++ b/Gemfile
@@ -14,7 +14,7 @@ group :development do
   gem "rake-compiler-dock", "1.3.1"
 
   # documentation
-  gem "hoe-markdown", "= 1.4.0"
+  gem "hoe-markdown", "1.5.1"
 
   # parser generator
   gem "rexical", "= 1.0.7"