diff --git a/.travis.yml b/.travis.yml
index f4e4330..887cd68 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,7 @@ language: ruby
 rvm:
   - 2.4.9
   - 2.6.5
+  - 2.7.2
 
 addons:
   postgresql: "9.4"
@@ -9,6 +10,7 @@ addons:
 env:
   - REDMINE_VER=3.4-stable
   - REDMINE_VER=4.1-stable
+  - REDMINE_VER=5.1-stable
 
 install: "echo skip bundle install"
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 82c5cfb..dbf27a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,12 @@
+# 1.7.7
+
+* Add compatibility with Redmine 5.1
+* Add 2FA OTP instructions
+
+# 1.7.6
+
+* Bump version after redmine_bots
+
 # 1.7.5
 
 * Fix problem with telegram_id exceeding int.
diff --git a/Gemfile b/Gemfile
index 172a537..4d4f5e2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,8 +1,8 @@
 source 'https://rubygems.org'
 
-gem 'active_model_otp', git: 'https://github.com/heapsource/active_model_otp.git', ref: '6ed9927'
-gem 'rotp', '~> 4.0'
-gem 'rqrcode', '~> 1.0'
+gem 'active_model_otp'
+gem 'rotp', '>= 5.0.0'
+gem 'rqrcode'
 
 group :test do
   gem 'shoulda', '~> 3.6'
diff --git a/init.rb b/init.rb
index b4cdeb6..2e08ca8 100644
--- a/init.rb
+++ b/init.rb
@@ -2,13 +2,17 @@
 
 FileUtils.mkdir_p(Rails.root.join('log/redmine_2fa')) unless Dir.exist?(Rails.root.join('log/redmine_2fa'))
 
-require 'redmine_two_fa'
+require './plugins/redmine_2fa/lib/redmine_two_fa'
 require 'telegram/bot'
 
-# Rails 5.1/Rails 4
-reloader = defined?(ActiveSupport::Reloader) ? ActiveSupport::Reloader : ActionDispatch::Reloader
-
-reloader.to_prepare do
+register_after_redmine_initialize_proc =
+  if Redmine::VERSION::MAJOR >= 5
+    Rails.application.config.public_method(:after_initialize)
+  else
+    reloader = defined?(ActiveSupport::Reloader) ? ActiveSupport::Reloader : ActionDispatch::Reloader
+    reloader.public_method(:to_prepare)
+  end
+register_after_redmine_initialize_proc.call do
   paths = '/lib/redmine_two_fa/{patches/*_patch,hooks/*_hook,*}.rb'
   Dir.glob(File.dirname(__FILE__) + paths).each do |file|
     require_dependency file
diff --git a/lib/redmine_two_fa/patches/application_controller_patch.rb b/lib/redmine_two_fa/patches/application_controller_patch.rb
deleted file mode 100644
index ffd9cd7..0000000
--- a/lib/redmine_two_fa/patches/application_controller_patch.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-module TwoFaApplicationControllerPatch
-  def find_current_user
-    user = super
-    return user unless api_request? || api_key_from_request.present?
-    return user unless Setting.rest_api_enabled? && Setting.plugin_redmine_2fa['restrict_api_access'] && accept_api_auth?
-    user&.api_allowed? ? user : nil
-  end
-end
-
-Rails.configuration.to_prepare do
-  ApplicationController.prepend(TwoFaApplicationControllerPatch)
-end
diff --git a/lib/redmine_two_fa/patches/two_fa_application_controller_patch.rb b/lib/redmine_two_fa/patches/two_fa_application_controller_patch.rb
new file mode 100644
index 0000000..266716c
--- /dev/null
+++ b/lib/redmine_two_fa/patches/two_fa_application_controller_patch.rb
@@ -0,0 +1,15 @@
+module RedmineTwoFa::Patches
+  module TwoFaApplicationControllerPatch
+    def find_current_user
+      user = super
+      return user unless api_request? || api_key_from_request.present?
+      return user unless Setting.rest_api_enabled? && Setting.plugin_redmine_2fa['restrict_api_access'] && accept_api_auth?
+      user&.api_allowed? ? user : nil
+    end
+  end
+end
+
+Rails.configuration.to_prepare do
+  ApplicationController.prepend(RedmineTwoFa::Patches::TwoFaApplicationControllerPatch)
+end
+