diff --git a/lib/redmine_custom_workflows/patches/mailer_patch.rb b/lib/redmine_custom_workflows/patches/mailer_patch.rb
index 01687f0..8ec898b 100644
--- a/lib/redmine_custom_workflows/patches/mailer_patch.rb
+++ b/lib/redmine_custom_workflows/patches/mailer_patch.rb
@@ -33,8 +33,8 @@ module RedmineCustomWorkflows
         template_params = headers.delete(:template_params) || {}
         if text_body || html_body
           mail headers do |format|
-            format.text { render :text => text_body } if text_body
-            format.html { render :text => html_body } if html_body
+            format.text { render text: text_body } if text_body
+            format.html { render text: html_body } if html_body
           end
         elsif template_name
           template_params.each { |k,v| instance_variable_set("@#{k}", v) }
@@ -43,7 +43,7 @@ module RedmineCustomWorkflows
             format.html { render template_name } unless Setting.plain_text_mail?
           end
         else
-          raise 'Not :text_body, :html_body or :template_name specified'
+          raise StandardError.new('Not :text_body, :html_body or :template_name specified')
         end
       end