diff --git a/faq.gemspec b/faq.gemspec
index c51bbf7..703b32a 100644
--- a/faq.gemspec
+++ b/faq.gemspec
@@ -5,6 +5,20 @@ require "faq/version"
 bundle_update_flag = ARGV[0]=='update' || ARGV[0]=='install'
 if bundle_update_flag
   env_pwd = ENV['PWD']
+  begin
+    require ::File.expand_path('app/helpers/bundler_helper.rb',  env_pwd)
+    extend BundlerHelper
+  rescue LoadError
+    def bundler_with_clean_env
+      if block_given?
+        if Bundler.respond_to?(:with_unbundled_env)
+          Bundler.with_unbundled_env(&Proc.new)
+        else
+          Bundler.with_clean_env(&Proc.new)
+        end
+      end
+    end
+  end
   app_path = File.expand_path(__dir__)
   template_path = env_pwd + '/app/templates'
   all_template = Dir.glob(template_path+'/*/')
@@ -38,9 +52,9 @@ if bundle_update_flag
                     copy_h["name"][locale] = copy_h["name"][locale].sub(/\d+/){|ff| last_index.to_s}
                   end
                   frontend_info << copy_h
-                  Bundler.with_clean_env{%x[cp -f #{app_path}/modules/faq/#{h["filename"]}.html.erb #{folder}modules/faq/#{copy_h["filename"]}.html.erb]}
+                  bundler_with_clean_env{%x[cp -f #{app_path}/modules/faq/#{h["filename"]}.html.erb #{folder}modules/faq/#{copy_h["filename"]}.html.erb]}
                 elsif h["force_cover"] == "true"
-                  Bundler.with_clean_env{%x[cp -f #{app_path}/modules/faq/#{h["filename"]}.html.erb #{folder}modules/faq/#{frontend_info[frontend_info_index]["filename"]}.html.erb]}
+                  bundler_with_clean_env{%x[cp -f #{app_path}/modules/faq/#{h["filename"]}.html.erb #{folder}modules/faq/#{frontend_info[frontend_info_index]["filename"]}.html.erb]}
                 end
               end
               if update_flag
@@ -62,7 +76,7 @@ if bundle_update_flag
         end
       else
         if !Dir.exist?(File.dirname(info_json_file)) && Dir.exist?(File.dirname(File.dirname(info_json_file)))
-          Bundler.with_clean_env{system ('cp -r '+ app_path + '/modules/ ' + folder)}
+          bundler_with_clean_env{system ('cp -r '+ app_path + '/modules/ ' + folder)}
         end
       end
     end