diff --git a/Gemfile b/Gemfile
index 2ada0849..07acc9da 100644
--- a/Gemfile
+++ b/Gemfile
@@ -67,7 +67,7 @@ gem 'email_validator'
 # Email address obfuscation
 gem 'actionview-encoded_mail_to'
 # To display a patched diff for event descriptions
-gem 'differ'
+gem 'diffy'
 
 # A generic library to administrate the tool
 gem 'activeadmin', github: 'gregbell/active_admin'
diff --git a/Gemfile.lock b/Gemfile.lock
index 8f1aa625..ae341dfd 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -101,7 +101,7 @@ GEM
       thread_safe (~> 0.1)
       warden (~> 1.2.3)
     devise-i18n (0.11.1)
-    differ (0.1.2)
+    diffy (3.0.6)
     docile (1.1.5)
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
@@ -329,7 +329,7 @@ DEPENDENCIES
   compass-rails
   devise
   devise-i18n
-  differ
+  diffy
   email_validator
   font-awesome-rails
   geocoder
diff --git a/app/controllers/moderations_controller.rb b/app/controllers/moderations_controller.rb
index b0473b9f..518a1b9e 100644
--- a/app/controllers/moderations_controller.rb
+++ b/app/controllers/moderations_controller.rb
@@ -1,5 +1,3 @@
-require 'differ'
-
 # Event management life cycle
 class ModerationsController < ApplicationController
   before_action :authenticate_user!
diff --git a/app/views/moderation_mailer/update.text.haml b/app/views/moderation_mailer/update.text.haml
index 1f226a8c..fba94102 100644
--- a/app/views/moderation_mailer/update.text.haml
+++ b/app/views/moderation_mailer/update.text.haml
@@ -10,7 +10,7 @@
 - prev = render file: '/events/show'
 - @event = former
 
-= raw Differ.diff new, prev
+= raw Diffy::Diff.new new, prev
 \
 - if @current_user
   = edit_moderation_url @event
diff --git a/test/mailers/moderation_mailer_test.rb b/test/mailers/moderation_mailer_test.rb
index a821d958..23646fb5 100644
--- a/test/mailers/moderation_mailer_test.rb
+++ b/test/mailers/moderation_mailer_test.rb
@@ -27,7 +27,8 @@ hello world'
     assert_match(/Édition de l'événement .*/, mail.subject)
     assert_equal ['moderateurs@agendadulibre.org'], mail.to
     assert_equal ['moderateurs@agendadulibre.org'], mail.from
-    assert_match(/^{/, mail.body.to_s)
+    assert_match(/^-/, mail.body.to_s)
+    assert_match(/^+/, mail.body.to_s)
   end
 
   test 'accept' do
diff --git a/test/mailers/previews/moderation_mailer_preview.rb b/test/mailers/previews/moderation_mailer_preview.rb
index 91608cea..55cfcc4a 100644
--- a/test/mailers/previews/moderation_mailer_preview.rb
+++ b/test/mailers/previews/moderation_mailer_preview.rb
@@ -1,5 +1,3 @@
-require 'differ'
-
 # Preview all emails at http://localhost:3000/rails/mailers/moderation_mailer
 class ModerationMailerPreview < ActionMailer::Preview
   # Preview this email at http://localhost:3000/rails/mailers/moderation_mailer/create