diff --git a/Gemfile b/Gemfile
index 1f9aee9..343cdd1 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ gem "actionpack-xml_parser"
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem 'tzinfo-data', platforms: [:mingw, :x64_mingw, :mswin, :jruby]
-gem "rbpdf", "~> 1.18.3"
+gem "rbpdf", "~> 1.18.4"
 
 # Optional gem for LDAP authentication
 group :ldap do