diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1795c8d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.history
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
index 2ace80f..feb78d3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,13 +11,13 @@ gemfile:
   - $REDMINE_PATH/Gemfile
 
 env:
-  - REDMINE_VER=3.1.6 DB=mysql
-  - REDMINE_VER=3.2.3 DB=mysql
-  - REDMINE_VER=3.3.0 DB=mysql
+  - REDMINE_VER=4.0.9 DB=mysql
+  - REDMINE_VER=4.1.3 DB=mysql
+  - REDMINE_VER=4.2.1 DB=mysql
 
-  - REDMINE_VER=3.1.6 DB=postgresql
-  - REDMINE_VER=3.2.3 DB=postgresql
-  - REDMINE_VER=3.3.0 DB=postgresql
+  - REDMINE_VER=4.0.9 DB=postgresql
+  - REDMINE_VER=4.1.3 DB=postgresql
+  - REDMINE_VER=4.2.1 DB=postgresql
 
 before_install:
   - export PLUGIN_NAME=redmine_custom_reports
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..525877f
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,17 @@
+# Changelog for Redmine Custom Reports
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## 1.0.0 - 2021-06-01
+
+### Added
+
+* Redmine 4.x support (no backward compatability!)
+* german translations
+
+### Fixed
+
+* controller tests
diff --git a/app/controllers/custom_reports_controller.rb b/app/controllers/custom_reports_controller.rb
index 7b53775..ebb41b9 100644
--- a/app/controllers/custom_reports_controller.rb
+++ b/app/controllers/custom_reports_controller.rb
@@ -1,11 +1,11 @@
 class CustomReportsController < ApplicationController
   unloadable
 
-  before_filter :find_project_by_project_id
-  before_filter :authorize
-  before_filter :find_custom_reports, only: [:index, :show, :new, :edit]
-  before_filter :find_custom_report, only: [:show, :edit, :update, :destroy]
-  before_filter :authorize_to_manage, only: [:edit, :update, :destroy]
+  before_action :find_project_by_project_id
+  before_action :authorize
+  before_action :find_custom_reports, only: [:index, :show, :new, :edit]
+  before_action :find_custom_report, only: [:show, :edit, :update, :destroy]
+  before_action :authorize_to_manage, only: [:edit, :update, :destroy]
 
   helper :queries
   include QueriesHelper
diff --git a/config/locales/de.yml b/config/locales/de.yml
new file mode 100644
index 0000000..1cd6c4a
--- /dev/null
+++ b/config/locales/de.yml
@@ -0,0 +1,26 @@
+de:
+  label_custom_report_plural: Eigene Auswertungen
+  label_custom_report_view_all: Alle Auswertungen
+  label_custom_report_new: Neue Auswertung
+  label_custom_report_public_list: Öffentliche Auswertungen
+  label_custom_report_own_list: Meine Auswertungen
+  label_custom_report_edit: Bearbeiten
+  label_series_filters: Ansicht
+
+  label_chart_type_undev_pie: "Undev Pie"
+  label_chart_type_pie: Kreis
+  label_chart_type_donut: Donut
+  label_chart_type_bar: Säulen
+  label_chart_type_horizontal_bar: Balken
+  label_chart_type_stacked_bar: Stapelbalken
+
+  field_chart_type: Diagrammtyp
+  field_null_text: Text für Nullwerte
+  field_series_name: Name der Ansicht
+
+  message_custom_reports_created: Auswertung erstellt
+  message_custom_reports_updated: Auswertung aktualisiert
+  message_custom_reports_destroyed: Auswertung gelöscht
+  message_cant_delete_last_series: Eine Auswertung muss mindestens eine Ansicht haben
+  message_add_custom_report_series: Ansicht hinzufügen
+  message_remove_custom_report_series: Ansicht löschen
diff --git a/db/migrate/20121212125001_create_custom_reports.rb b/db/migrate/20121212125001_create_custom_reports.rb
index 0f4d54f..1246477 100644
--- a/db/migrate/20121212125001_create_custom_reports.rb
+++ b/db/migrate/20121212125001_create_custom_reports.rb
@@ -1,4 +1,4 @@
-class CreateCustomReports < ActiveRecord::Migration
+class CreateCustomReports < ActiveRecord::Migration[5.2]
   def self.up
     unless table_exists? :custom_reports
       create_table :custom_reports do |t|
diff --git a/db/migrate/20121212125002_create_custom_report_series.rb b/db/migrate/20121212125002_create_custom_report_series.rb
index 9f06771..472d52c 100644
--- a/db/migrate/20121212125002_create_custom_report_series.rb
+++ b/db/migrate/20121212125002_create_custom_report_series.rb
@@ -1,4 +1,4 @@
-class CreateCustomReportSeries < ActiveRecord::Migration
+class CreateCustomReportSeries < ActiveRecord::Migration[5.2]
   def self.up
     unless table_exists? :custom_report_series
       create_table :custom_report_series do |t|
diff --git a/db/migrate/20121212125003_remove_filters_from_custom_reports.rb b/db/migrate/20121212125003_remove_filters_from_custom_reports.rb
index ea25177..aa8cb82 100644
--- a/db/migrate/20121212125003_remove_filters_from_custom_reports.rb
+++ b/db/migrate/20121212125003_remove_filters_from_custom_reports.rb
@@ -1,4 +1,4 @@
-class RemoveFiltersFromCustomReports < ActiveRecord::Migration
+class RemoveFiltersFromCustomReports < ActiveRecord::Migration[5.2]
   def self.up
     if column_exists? :custom_reports, :filters
       remove_column :custom_reports, :filters
diff --git a/init.rb b/init.rb
index c06a5b6..c40497b 100644
--- a/init.rb
+++ b/init.rb
@@ -2,7 +2,7 @@
   name 'Redmine Custom Reports (with charts) plugin'
   author 'Restream'
   description 'Redmine plugin for custom reports with charts'
-  version '0.1.5'
+  version '1.0.0'
   url 'https://github.com/Restream/redmine_custom_reports'
   author_url 'https://github.com/Restream'
 
diff --git a/lib/redmine_custom_reports.rb b/lib/redmine_custom_reports.rb
index 1a15c5f..8a9be2c 100644
--- a/lib/redmine_custom_reports.rb
+++ b/lib/redmine_custom_reports.rb
@@ -1,4 +1,4 @@
-ActionDispatch::Callbacks.to_prepare do
+ActiveSupport::Reloader.to_prepare do
 
   # Requiring plugin's controller and model
   require_dependency 'custom_report'
@@ -11,4 +11,4 @@
   load 'redmine_custom_reports/project_patch.rb'
   load 'redmine_custom_reports/user_patch.rb'
 
-end
\ No newline at end of file
+end
diff --git a/test/functional/custom_reports_controller_test.rb b/test/functional/custom_reports_controller_test.rb
index 4f3ffe9..656e390 100644
--- a/test/functional/custom_reports_controller_test.rb
+++ b/test/functional/custom_reports_controller_test.rb
@@ -16,7 +16,6 @@ def setup
     @user        = User.find(1)
     User.current = @user
 
-    @request                   = ActionController::TestRequest.new
     @request.session[:user_id] = @user.id
 
     @custom_report = @project.custom_reports.create!(
@@ -34,17 +33,17 @@ def setup
   end
 
   def test_show_all_custom_reports
-    get :index, project_id: @project.identifier
+    get :index, params: { project_id: @project.identifier }
     assert_response :success
   end
 
   def test_show_custom_report
-    get :new, project_id: @project.identifier, id: @custom_report.id
+    get :new, params: { project_id: @project.identifier, id: @custom_report.id }
     assert_response :success
   end
 
   def test_show_new_custom_report
-    get :new, project_id: @project.identifier
+    get :new, params: { project_id: @project.identifier }
     assert_response :success
   end
 
@@ -69,7 +68,7 @@ def test_create_custom_report
         }
       }
     }
-    post :create, project_id: @project.identifier, custom_report: attrs
+    post :create, params: { project_id: @project.identifier, custom_report: attrs }
     assert_response :redirect
     custom_report = @project.custom_reports.find_by_name(attrs[:name])
     assert custom_report
@@ -86,7 +85,7 @@ def test_create_custom_report
   end
 
   def test_show_edit_custom_report
-    get :edit, project_id: @project.identifier, id: @custom_report.id
+    get :edit, params: { project_id: @project.identifier, id: @custom_report.id }
     assert_response :success
   end
 
@@ -116,7 +115,7 @@ def test_update_custom_report
         }
       }
     }
-    put :update, project_id: @project.identifier, id: @custom_report.id, custom_report: attrs
+    put :update, params: { project_id: @project.identifier, id: @custom_report.id, custom_report: attrs }
     assert_response :redirect
     @custom_report.reload
     assert_equal attrs[:description], @custom_report.description
@@ -132,7 +131,7 @@ def test_update_custom_report
   end
 
   def test_destroy_custom_report
-    delete :destroy, project_id: @project.identifier, id: @custom_report.id
+    delete :destroy, params: { project_id: @project.identifier, id: @custom_report.id }
     assert_response :redirect
     custom_report = CustomReport.find_by_id @custom_report.id
     assert_nil custom_report