diff --git a/Gemfile b/Gemfile
index a60eac29..44094e50 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,16 +4,17 @@ source 'http://rubygems.org'
 # TODO: temporary disable http, until ruby upgrade with new openssl
 # source 'https://rubygems.org'
 
-gem 'rails', '4.2.11'
-
-gem 'pg', '~> 0.15.1'
+gem 'rails', '~> 5.2', '>= 5.2.3'
+gem 'pg'
 gem 'pghero'
 gem 'thin'
 
 gem 'chartkick'
 
 gem 'aasm'
-gem 'activemerchant', '~> 1.32.1'
+gem 'activemerchant', '~> 1.93'
+gem 'money'
+gem 'offsite_payments'
 gem 'bootstrap', '~> 4.2.1'
 gem 'cancan'
 gem 'clockwork'
@@ -27,14 +28,14 @@ gem 'slim'
 # Temporary broken with rails 4.2
 gem 'active_model_serializers' # , github: 'rails-api/active_model_serializers', branch: '0-9-stable'
 
-gem 'ransack', '1.5.1'
+gem 'ransack', '2.1.1'
 
 # TODO: switch to stable version
 gem 'carrierwave'
-gem 'draper', '1.4.0'
+gem 'draper', '3.1'
 gem 'gibbon'
 gem 'mechanize'
-gem 'rails_config'
+gem 'config'
 gem 'russian_central_bank'
 gem 'show_for', github: 'plataformatec/show_for'
 gem 'whenever', '0.9.0', require: false
@@ -46,11 +47,11 @@ gem 'rollbar'
 # TODO: make it optional via ENV flag
 gem 'newrelic_rpm'
 
-gem 'json', '~> 1.8'
+gem 'json', '~> 2.2'
 gem 'thread_safe', '0.3.6'
 
 group :assets do
-  gem 'coffee-rails', '~> 4.1.0'
+  gem 'coffee-rails', '~> 5.0'
   gem 'sass-rails'
   gem 'uglifier'
 end
@@ -59,7 +60,7 @@ gem 'jquery-rails'
 gem 'jquery-ui-rails'
 
 gem 'ffi', '>= 1.9.24'
-gem 'jbuilder', '~> 1.0.1'
+gem 'jbuilder', '~> 2.8'
 
 group :development do
   gem 'better_errors'
@@ -68,7 +69,7 @@ group :development do
   gem 'migration_opener'
   gem 'rubocop', require: false
   gem 'sandi_meter', require: false
-  gem 'web-console', '~> 2.0'
+  gem 'web-console', '~> 3.7'
 end
 
 group :test, :development do
@@ -95,4 +96,5 @@ group :test do
   gem 'clockwork-test'
   gem 'fakeweb', github: 'chrisk/fakeweb'
   gem 'zonebie'
+  gem 'rails-controller-testing'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index dded63b8..45984b4b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,79 +6,86 @@ GIT
 
 GIT
   remote: git://github.com/plataformatec/show_for.git
-  revision: 7f2dc583ee84e9fd86d00c70c5e63027b20a8efc
+  revision: 28166bfd03dc7b9ad54ec2f9939b5b24c8aff76f
   specs:
-    show_for (0.3.0.rc)
-      actionpack (>= 3.2, < 5)
-      activemodel (>= 3.2, < 5)
+    show_for (0.6.1)
+      actionpack (>= 4.1)
+      activemodel (>= 4.1)
 
 GEM
   remote: http://rubygems.org/
   specs:
     aasm (5.0.1)
       concurrent-ruby (~> 1.0)
-    actionmailer (4.2.11)
-      actionpack (= 4.2.11)
-      actionview (= 4.2.11)
-      activejob (= 4.2.11)
+    actioncable (5.2.3)
+      actionpack (= 5.2.3)
+      nio4r (~> 2.0)
+      websocket-driver (>= 0.6.1)
+    actionmailer (5.2.3)
+      actionpack (= 5.2.3)
+      actionview (= 5.2.3)
+      activejob (= 5.2.3)
       mail (~> 2.5, >= 2.5.4)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
-    actionpack (4.2.11)
-      actionview (= 4.2.11)
-      activesupport (= 4.2.11)
-      rack (~> 1.6)
-      rack-test (~> 0.6.2)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      rails-dom-testing (~> 2.0)
+    actionpack (5.2.3)
+      actionview (= 5.2.3)
+      activesupport (= 5.2.3)
+      rack (~> 2.0)
+      rack-test (>= 0.6.3)
+      rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (4.2.11)
-      activesupport (= 4.2.11)
+    actionview (5.2.3)
+      activesupport (= 5.2.3)
       builder (~> 3.1)
-      erubis (~> 2.7.0)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
     active_model_serializers (0.8.1)
       activemodel (>= 3.0)
-    active_utils (1.0.5)
-      activesupport (>= 2.3.11)
-      i18n
-    activejob (4.2.11)
-      activesupport (= 4.2.11)
-      globalid (>= 0.3.0)
-    activemerchant (1.32.1)
-      active_utils (>= 1.0.2)
-      activesupport (>= 2.3.14)
-      builder (>= 2.0.0)
+    active_utils (3.3.16)
+      activesupport (>= 4.2)
       i18n
-      json (>= 1.5.1)
-      money
-      nokogiri
-    activemodel (4.2.11)
-      activesupport (= 4.2.11)
+    activejob (5.2.3)
+      activesupport (= 5.2.3)
+      globalid (>= 0.3.6)
+    activemerchant (1.95.0)
+      activesupport (>= 4.2)
+      builder (>= 2.1.2, < 4.0.0)
+      i18n (>= 0.6.9)
+      nokogiri (~> 1.4)
+    activemodel (5.2.3)
+      activesupport (= 5.2.3)
+    activemodel-serializers-xml (1.0.2)
+      activemodel (> 5.x)
+      activesupport (> 5.x)
       builder (~> 3.1)
-    activerecord (4.2.11)
-      activemodel (= 4.2.11)
-      activesupport (= 4.2.11)
-      arel (~> 6.0)
-    activesupport (4.2.11)
-      i18n (~> 0.7)
+    activerecord (5.2.3)
+      activemodel (= 5.2.3)
+      activesupport (= 5.2.3)
+      arel (>= 9.0)
+    activestorage (5.2.3)
+      actionpack (= 5.2.3)
+      activerecord (= 5.2.3)
+      marcel (~> 0.3.1)
+    activesupport (5.2.3)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
       minitest (~> 5.1)
-      thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
     addressable (2.3.4)
     akami (1.2.1)
       gyoku (>= 0.4.0)
       nokogiri
-    arel (6.0.4)
+    arel (9.0.0)
     ast (2.4.0)
-    autoprefixer-rails (9.4.4)
+    autoprefixer-rails (9.6.0)
       execjs
-    bcrypt (3.1.12)
+    bcrypt (3.1.13)
     better_errors (2.5.1)
       coderay (>= 1.0.0)
       erubi (>= 1.0.0)
       rack (>= 0.9.0)
-    binding_of_caller (0.7.2)
-      debug_inspector (>= 0.0.1)
+    bindex (0.7.0)
     bootstrap (4.2.1)
       autoprefixer-rails (>= 9.1.0)
       popper_js (>= 1.14.3, < 2)
@@ -110,26 +117,30 @@ GEM
       clockwork
       timecop
     coderay (1.1.2)
-    coffee-rails (4.1.1)
+    coffee-rails (5.0.0)
       coffee-script (>= 2.2.0)
-      railties (>= 4.0.0, < 5.1.x)
+      railties (>= 5.2.0)
     coffee-script (2.4.1)
       coffee-script-source
       execjs
     coffee-script-source (1.12.2)
-    concurrent-ruby (1.1.4)
+    concurrent-ruby (1.1.5)
+    config (1.7.1)
+      activesupport (>= 3.0)
+      deep_merge (~> 1.2.1)
+      dry-validation (>= 0.12.2)
     connection_pool (2.2.2)
     crass (1.0.4)
     daemons (1.2.6)
     database_cleaner (1.0.0.RC1)
-    debug_inspector (0.0.2)
+    deep_merge (1.2.1)
     devise (4.5.0)
       bcrypt (~> 3.0)
       orm_adapter (~> 0.1)
       railties (>= 4.1.0, < 6.0)
       responders
       warden (~> 1.2.3)
-    devise-i18n (0.10.3)
+    devise-i18n (0.10.5)
     diff-lcs (1.3)
     docile (1.3.1)
     domain_name (0.5.19)
@@ -138,13 +149,41 @@ GEM
     dotenv-rails (2.6.0)
       dotenv (= 2.6.0)
       railties (>= 3.2, < 6.0)
-    draper (1.4.0)
-      actionpack (>= 3.0)
-      activemodel (>= 3.0)
-      activesupport (>= 3.0)
-      request_store (~> 1.0)
+    draper (3.1.0)
+      actionpack (>= 5.0)
+      activemodel (>= 5.0)
+      activemodel-serializers-xml (>= 1.0)
+      activesupport (>= 5.0)
+      request_store (>= 1.0)
+    dry-configurable (0.8.3)
+      concurrent-ruby (~> 1.0)
+      dry-core (~> 0.4, >= 0.4.7)
+    dry-container (0.7.0)
+      concurrent-ruby (~> 1.0)
+      dry-configurable (~> 0.1, >= 0.1.3)
+    dry-core (0.4.7)
+      concurrent-ruby (~> 1.0)
+    dry-equalizer (0.2.2)
+    dry-inflector (0.1.2)
+    dry-logic (0.6.1)
+      concurrent-ruby (~> 1.0)
+      dry-core (~> 0.2)
+      dry-equalizer (~> 0.2)
+    dry-types (0.14.1)
+      concurrent-ruby (~> 1.0)
+      dry-container (~> 0.3)
+      dry-core (~> 0.4, >= 0.4.4)
+      dry-equalizer (~> 0.2)
+      dry-inflector (~> 0.1, >= 0.1.2)
+      dry-logic (~> 0.5, >= 0.5)
+    dry-validation (0.13.3)
+      concurrent-ruby (~> 1.0)
+      dry-configurable (~> 0.1, >= 0.1.3)
+      dry-core (~> 0.2, >= 0.2.1)
+      dry-equalizer (~> 0.2)
+      dry-logic (~> 0.5, >= 0.5.0)
+      dry-types (~> 0.14.0)
     erubi (1.8.0)
-    erubis (2.7.0)
     eventmachine (1.2.7)
     execjs (2.7.0)
     factory_girl (4.2.0)
@@ -154,15 +193,17 @@ GEM
       railties (>= 3.0.0)
     faker (1.9.3)
       i18n (>= 0.7)
+    faraday (0.15.4)
+      multipart-post (>= 1.2, < 3)
     ffi (1.9.25)
     font-awesome-sass (5.6.1)
       sassc (>= 1.11)
     foreman (0.63.0)
       dotenv (>= 0.7)
       thor (>= 0.13.6)
-    gibbon (1.1.5)
-      httparty
-      multi_json (>= 1.9.0)
+    gibbon (3.2.0)
+      faraday (>= 0.9.1)
+      multi_json (>= 1.11.0)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
     gyoku (1.1.1)
@@ -170,9 +211,6 @@ GEM
     highline (2.0.0)
     http-cookie (1.0.2)
       domain_name (~> 0.5)
-    httparty (0.13.3)
-      json (~> 1.8)
-      multi_xml (>= 0.5.2)
     httpi (2.1.0)
       rack
       rubyntlm (~> 0.3.2)
@@ -188,15 +226,16 @@ GEM
       rainbow (>= 2.2.2, < 4.0)
       terminal-table (>= 1.5.1)
     jaro_winkler (1.5.2)
-    jbuilder (1.0.2)
-      activesupport (>= 3.0.0)
+    jbuilder (2.8.0)
+      activesupport (>= 4.2.0)
+      multi_json (>= 1.2)
     jquery-rails (4.3.3)
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
     jquery-ui-rails (4.0.5)
       railties (>= 3.1.0)
-    json (1.8.6)
+    json (2.2.0)
     kaminari (1.1.1)
       activesupport (>= 4.1.0)
       kaminari-actionview (= 1.1.1)
@@ -218,6 +257,8 @@ GEM
       nokogiri (>= 1.5.9)
     mail (2.7.1)
       mini_mime (>= 0.1.1)
+    marcel (0.3.3)
+      mimemagic (~> 0.3.2)
     mechanize (2.7.2)
       domain_name (~> 0.5, >= 0.5.1)
       http-cookie (~> 1.0.0)
@@ -231,6 +272,7 @@ GEM
     migration_opener (0.0.3)
       rails
     mime-types (1.25.1)
+    mimemagic (0.3.3)
     mini_mime (1.0.1)
     mini_portile2 (2.4.0)
     minitest (5.11.3)
@@ -238,24 +280,32 @@ GEM
     money (6.5.0)
       i18n (>= 0.6.4, <= 0.7.0)
     multi_json (1.13.1)
-    multi_xml (0.5.5)
+    multipart-post (2.1.1)
+    mustermann (1.0.3)
     net-http-digest_auth (1.4)
     net-http-persistent (2.9.4)
     newrelic_rpm (5.6.0.349)
-    nokogiri (1.10.1)
+    nio4r (2.3.1)
+    nokogiri (1.10.3)
       mini_portile2 (~> 2.4.0)
     nori (2.3.0)
     ntlm-http (0.1.1)
+    offsite_payments (2.7.13)
+      actionpack (>= 5.2.3)
+      actionview (>= 5.1.6.2)
+      active_utils (~> 3.3.0)
+      activesupport (>= 5.2.3)
+      builder (>= 2.1.2, < 4.0.0)
+      i18n (>= 0.6.6)
+      nokogiri (>= 1.8.5)
     orm_adapter (0.5.0)
     parallel (1.13.0)
     parser (2.6.0.0)
       ast (~> 2.4.0)
-    pg (0.15.1)
+    pg (1.1.4)
     pghero (0.1.3)
       activerecord
       pg
-    polyamorous (1.1.0)
-      activerecord (>= 3.0)
     popper_js (1.14.5)
     powerpack (0.1.2)
     pry (0.12.2)
@@ -264,56 +314,58 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     psych (3.1.0)
-    rack (1.6.11)
-    rack-protection (1.5.5)
+    rack (2.0.7)
+    rack-protection (2.0.5)
       rack
-    rack-test (0.6.3)
-      rack (>= 1.0)
-    rails (4.2.11)
-      actionmailer (= 4.2.11)
-      actionpack (= 4.2.11)
-      actionview (= 4.2.11)
-      activejob (= 4.2.11)
-      activemodel (= 4.2.11)
-      activerecord (= 4.2.11)
-      activesupport (= 4.2.11)
-      bundler (>= 1.3.0, < 2.0)
-      railties (= 4.2.11)
-      sprockets-rails
-    rails-deprecated_sanitizer (1.0.3)
-      activesupport (>= 4.2.0.alpha)
-    rails-dom-testing (1.0.9)
-      activesupport (>= 4.2.0, < 5.0)
-      nokogiri (~> 1.6)
-      rails-deprecated_sanitizer (>= 1.0.1)
+    rack-test (1.1.0)
+      rack (>= 1.0, < 3)
+    rails (5.2.3)
+      actioncable (= 5.2.3)
+      actionmailer (= 5.2.3)
+      actionpack (= 5.2.3)
+      actionview (= 5.2.3)
+      activejob (= 5.2.3)
+      activemodel (= 5.2.3)
+      activerecord (= 5.2.3)
+      activestorage (= 5.2.3)
+      activesupport (= 5.2.3)
+      bundler (>= 1.3.0)
+      railties (= 5.2.3)
+      sprockets-rails (>= 2.0.0)
+    rails-controller-testing (1.0.4)
+      actionpack (>= 5.0.1.x)
+      actionview (>= 5.0.1.x)
+      activesupport (>= 5.0.1.x)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
     rails-html-sanitizer (1.0.4)
       loofah (~> 2.2, >= 2.2.2)
     rails-i18n (0.7.3)
       i18n (~> 0.5)
-    rails_config (0.3.3)
-      activesupport (>= 3.0)
-    railties (4.2.11)
-      actionpack (= 4.2.11)
-      activesupport (= 4.2.11)
+    railties (5.2.3)
+      actionpack (= 5.2.3)
+      activesupport (= 5.2.3)
+      method_source
       rake (>= 0.8.7)
-      thor (>= 0.18.1, < 2.0)
+      thor (>= 0.19.0, < 2.0)
     rainbow (3.0.0)
     rake (12.3.2)
-    ransack (1.5.1)
-      actionpack (>= 3.0)
-      activerecord (>= 3.0)
-      activesupport (>= 3.0)
+    ransack (2.1.1)
+      actionpack (>= 5.0)
+      activerecord (>= 5.0)
+      activesupport (>= 5.0)
       i18n
-      polyamorous (~> 1.1)
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)
       ffi (~> 1.0)
     redis (4.1.0)
     regexp_parser (1.3.0)
-    request_store (1.1.0)
-    responders (2.4.0)
-      actionpack (>= 4.2.0, < 5.3)
-      railties (>= 4.2.0, < 5.3)
+    request_store (1.4.1)
+      rack (>= 1.4)
+    responders (2.4.1)
+      actionpack (>= 4.2.0, < 6.0)
+      railties (>= 4.2.0, < 6.0)
     rollbar (2.18.2)
       multi_json
     rspec-core (3.8.0)
@@ -365,10 +417,10 @@ GEM
       sprockets (>= 2.8, < 4.0)
       sprockets-rails (>= 2.0, < 4.0)
       tilt (>= 1.1, < 3)
-    sassc (2.0.0)
-      ffi (~> 1.9.6)
+    sassc (2.0.1)
+      ffi (~> 1.9)
       rake
-    sassc-rails (2.1.0)
+    sassc-rails (2.1.1)
       railties (>= 4.0.0)
       sassc (>= 2.0)
       sprockets (> 3.0)
@@ -400,10 +452,11 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
-    sinatra (1.4.8)
-      rack (~> 1.5)
-      rack-protection (~> 1.4)
-      tilt (>= 1.3, < 3)
+    sinatra (2.0.5)
+      mustermann (~> 1.0)
+      rack (~> 2.0)
+      rack-protection (= 2.0.5)
+      tilt (~> 2.0)
     slim (4.0.1)
       temple (>= 0.7.6, < 0.9)
       tilt (>= 2.0.6, < 2.1)
@@ -434,18 +487,21 @@ GEM
     unf_ext (0.0.6)
     unicode-display_width (1.4.1)
     vcr (4.0.0)
-    warden (1.2.7)
-      rack (>= 1.0)
+    warden (1.2.8)
+      rack (>= 2.0.6)
     wasabi (3.2.3)
       httpi (~> 2.0)
       mime-types (< 2.0.0)
       nokogiri (>= 1.4.0)
-    web-console (2.0.0)
-      activemodel (~> 4.0)
-      binding_of_caller (>= 0.7.2)
-      railties (~> 4.0)
-      sprockets-rails (>= 2.0, < 4.0)
+    web-console (3.7.0)
+      actionview (>= 5.0)
+      activemodel (>= 5.0)
+      bindex (>= 0.4.0)
+      railties (>= 5.0)
     webrobots (0.1.1)
+    websocket-driver (0.7.0)
+      websocket-extensions (>= 0.1.0)
+    websocket-extensions (0.1.3)
     whenever (0.9.0)
       activesupport (>= 2.3.4)
       chronic (>= 0.6.3)
@@ -459,7 +515,7 @@ PLATFORMS
 DEPENDENCIES
   aasm
   active_model_serializers
-  activemerchant (~> 1.32.1)
+  activemerchant (~> 1.93)
   better_errors
   bootstrap (~> 4.2.1)
   cancan
@@ -469,12 +525,13 @@ DEPENDENCIES
   chartkick
   clockwork
   clockwork-test
-  coffee-rails (~> 4.1.0)
+  coffee-rails (~> 5.0)
+  config
   database_cleaner (= 1.0.0.RC1)
   devise (= 4.5.0)
   devise-i18n (~> 0.10.3)
   dotenv-rails
-  draper (= 1.4.0)
+  draper (= 3.1)
   factory_girl_rails (~> 4.0)
   faker
   fakeweb!
@@ -483,22 +540,24 @@ DEPENDENCIES
   foreman
   gibbon
   i18n-tasks (~> 0.9.28)
-  jbuilder (~> 1.0.1)
+  jbuilder (~> 2.8)
   jquery-rails
   jquery-ui-rails
-  json (~> 1.8)
+  json (~> 2.2)
   kaminari
   letter_opener
   mechanize
   migration_opener
+  money
   newrelic_rpm
-  pg (~> 0.15.1)
+  offsite_payments
+  pg
   pghero
   pry-rails
-  rails (= 4.2.11)
+  rails (~> 5.2, >= 5.2.3)
+  rails-controller-testing
   rails-i18n
-  rails_config
-  ransack (= 1.5.1)
+  ransack (= 2.1.1)
   rollbar
   rspec-its
   rspec-rails (~> 3.8)
@@ -519,7 +578,7 @@ DEPENDENCIES
   timecop
   uglifier
   vcr
-  web-console (~> 2.0)
+  web-console (~> 3.7)
   whenever (= 0.9.0)
   zonebie
 
diff --git a/app/controllers/admin/change_languages_controller.rb b/app/controllers/admin/change_languages_controller.rb
index 608149b1..d899547b 100644
--- a/app/controllers/admin/change_languages_controller.rb
+++ b/app/controllers/admin/change_languages_controller.rb
@@ -10,7 +10,7 @@ def update
 
     def set_session_and_redirect
       session[:locale] = I18n.locale
-      redirect_to :back
+      redirect_back fallback_location: admin_change_languages_path(locale: session[:locale])
     end
   end
 end
diff --git a/app/controllers/admin/users_controller.rb b/app/controllers/admin/users_controller.rb
index da392bde..9c5f89b9 100644
--- a/app/controllers/admin/users_controller.rb
+++ b/app/controllers/admin/users_controller.rb
@@ -63,7 +63,7 @@ def payment
 
     def emails_export
       users = User.search(search_params).result
-      render text: Admin::UsersSerializer.new(users, :csv).emails
+      render plain: Admin::UsersSerializer.new(users, :csv).emails
     end
 
     def enable_test_period
diff --git a/app/controllers/api/authentication_controller.rb b/app/controllers/api/authentication_controller.rb
index 3c13e21c..8f13b6ad 100644
--- a/app/controllers/api/authentication_controller.rb
+++ b/app/controllers/api/authentication_controller.rb
@@ -13,9 +13,9 @@ class AuthenticationController < Api::BaseController
     def auth
       authenticator = Authenticator.new(params[:login], params[:password], params[:hostname])
       if authenticator.valid_credentials?
-        render status: 200, nothing: true
+        render status: 200, body: nil
       else
-        render status: 404, nothing: true
+        render status: 404, body: nil
       end
     end
   end
diff --git a/app/controllers/billing/merchant_controller.rb b/app/controllers/billing/merchant_controller.rb
index 59993f73..6b207ffc 100644
--- a/app/controllers/billing/merchant_controller.rb
+++ b/app/controllers/billing/merchant_controller.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class Billing::MerchantController < Billing::BaseController
-  skip_before_filter :check_authorization, :verify_authenticity_token
+  skip_before_action :check_authorization, :verify_authenticity_token
   before_action :check_if_pay_system_is_enabled, only: [:result]
 
   def success
diff --git a/app/controllers/billing/options_controller.rb b/app/controllers/billing/options_controller.rb
index a3b610ad..47545e49 100644
--- a/app/controllers/billing/options_controller.rb
+++ b/app/controllers/billing/options_controller.rb
@@ -22,7 +22,7 @@ def destroy
   def update
     option = current_user.user_options.find_by(option_id: params[:id])
     option.update(attrs: params[:option_attributes])
-    render nothing: true
+    head :ok
   end
 
   def toggle
diff --git a/app/controllers/billing/paypal_controller.rb b/app/controllers/billing/paypal_controller.rb
index 51976e00..f0f303f1 100644
--- a/app/controllers/billing/paypal_controller.rb
+++ b/app/controllers/billing/paypal_controller.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class Billing::PaypalController < Billing::MerchantController
-  include ActiveMerchant::Billing::Integrations
+  include OffsitePayments::Integrations
 
   def result
     if notitication.acknowledge
diff --git a/app/controllers/billing/robokassa_controller.rb b/app/controllers/billing/robokassa_controller.rb
index 50a78399..69ef32d6 100644
--- a/app/controllers/billing/robokassa_controller.rb
+++ b/app/controllers/billing/robokassa_controller.rb
@@ -3,13 +3,13 @@
 # This controller contains endpoints for Robokassa paysystem HTTP callbacks,
 # that notifies system about incoming payments.
 class Billing::RobokassaController < Billing::MerchantController
-  include ActiveMerchant::Billing::Integrations
+  include OffsitePayments::Integrations
 
-  before_filter :create_notification
+  before_action :create_notification
 
   def result
     if @notification.acknowledge
-      render text: 'Done'
+      render plain: 'Done'
       payment.accept!
     else
       raise 'Invalid robokassa notification'
diff --git a/app/controllers/billing/webmoney_controller.rb b/app/controllers/billing/webmoney_controller.rb
index 93749d2e..1c8a050e 100644
--- a/app/controllers/billing/webmoney_controller.rb
+++ b/app/controllers/billing/webmoney_controller.rb
@@ -3,15 +3,15 @@
 # This controller contains endpoints for Webmoney paysystem HTTP callbacks,
 # that notifies system about incoming payments.
 class Billing::WebmoneyController < Billing::MerchantController
-  include ActiveMerchant::Billing::Integrations
+  include OffsitePayments::Integrations
 
-  before_filter :create_notification
+  before_action :create_notification
 
   def result
     if @notification.key_present?
       if @notification.recognizes?
         if @notification.acknowledge
-          render text: 'Done'
+          render plain: 'Done'
           payment.accept!
         else
           raise 'Invalid webmoney verification key'
@@ -20,7 +20,7 @@ def result
         raise 'Undefined transaction_item_id'
       end
     else
-      render text: 'YES'
+      render plain: 'YES'
     end
   end
 
diff --git a/app/models/server/signature.rb b/app/models/server/signature.rb
index da01b241..0bd26028 100644
--- a/app/models/server/signature.rb
+++ b/app/models/server/signature.rb
@@ -15,7 +15,7 @@ class Signature
 
     def initialize(server, request_params)
       @server         = server
-      @request_params = request_params.with_indifferent_access
+      @request_params = with_indifferent_access(request_params)
     end
 
     def valid?
@@ -32,6 +32,14 @@ def signature
       request_params[:signature]
     end
 
+    def with_indifferent_access(request_params)
+      if request_params.instance_of? Hash
+        request_params.with_indifferent_access
+      else
+        request_params.to_unsafe_h.with_indifferent_access
+      end
+    end
+
     def clean_params
       IGNORED_PARAMS.each_with_object(request_params.dup) do |param, attrs|
         attrs.delete(param)
diff --git a/app/models/withdrawal.rb b/app/models/withdrawal.rb
index 9efd5c29..e7e3e3a5 100644
--- a/app/models/withdrawal.rb
+++ b/app/models/withdrawal.rb
@@ -7,7 +7,7 @@ class Withdrawal < ActiveRecord::Base
   has_many :withdrawal_prolongations
 
   validates :amount, :user_id, :plan_id, presence: true
-  validate :balance_greater_than_amount, on: :create, if: 'user.present? && amount.present?'
+  validate :balance_greater_than_amount, on: :create, if: -> { 'user.present? && amount.present?' }
 
   after_create :decrease_user_balance
 
diff --git a/app/services/newsletter_manager.rb b/app/services/newsletter_manager.rb
index 0d40967f..7674fe18 100644
--- a/app/services/newsletter_manager.rb
+++ b/app/services/newsletter_manager.rb
@@ -4,7 +4,7 @@ class NewsletterManager
   attr_reader :api
 
   def initialize
-    @api = ::Gibbon::API.new(Settings.mailchimp.api_key)
+    @api = Gibbon::Request.new(api_key: Settings.mailchimp.api_key)
   end
 
   def add_to_list(email, list_name)
diff --git a/app/views/billing/payments/forms/_cc.html.slim b/app/views/billing/payments/forms/_cc.html.slim
index e71ca4d7..fe6b48e0 100644
--- a/app/views/billing/payments/forms/_cc.html.slim
+++ b/app/views/billing/payments/forms/_cc.html.slim
@@ -1,5 +1,5 @@
-- require 'active_merchant/billing/integrations/action_view_helper'
-- ActionView::Base.send(:include, ActiveMerchant::Billing::Integrations::ActionViewHelper)
+- require 'offsite_payments/action_view_helper'
+- ActionView::Base.send(:include, OffsitePayments::ActionViewHelper)
 
 = payment_service_for @payment.id, Settings.robokassa.login,
                         :amount => @payment.amount,
diff --git a/app/views/billing/payments/forms/_wmr.html.slim b/app/views/billing/payments/forms/_wmr.html.slim
index e6fc7caa..811ab459 100644
--- a/app/views/billing/payments/forms/_wmr.html.slim
+++ b/app/views/billing/payments/forms/_wmr.html.slim
@@ -1,5 +1,5 @@
-- require 'active_merchant/billing/integrations/action_view_helper'
-- ActionView::Base.send(:include, ActiveMerchant::Billing::Integrations::ActionViewHelper)
+- require 'offsite_payments/action_view_helper'
+- ActionView::Base.send(:include, OffsitePayments::ActionViewHelper)
 
 = payment_service_for @payment.id, Settings.webmoney.wallet.wmr,
                         :amount => @payment.amount,
diff --git a/app/views/billing/payments/forms/_wmz.html.slim b/app/views/billing/payments/forms/_wmz.html.slim
index d9070819..16178f05 100644
--- a/app/views/billing/payments/forms/_wmz.html.slim
+++ b/app/views/billing/payments/forms/_wmz.html.slim
@@ -1,5 +1,5 @@
-- require 'active_merchant/billing/integrations/action_view_helper'
-- ActionView::Base.send(:include, ActiveMerchant::Billing::Integrations::ActionViewHelper)
+- require 'offsite_payments/action_view_helper'
+- ActionView::Base.send(:include, OffsitePayments::ActionViewHelper)
 
 = payment_service_for @payment.id, Settings.webmoney.wallet.wmz,
                         :amount => @payment.amount,
diff --git a/app/views/billing/payments/forms/_yandex.html.slim b/app/views/billing/payments/forms/_yandex.html.slim
index e71ca4d7..fe6b48e0 100644
--- a/app/views/billing/payments/forms/_yandex.html.slim
+++ b/app/views/billing/payments/forms/_yandex.html.slim
@@ -1,5 +1,5 @@
-- require 'active_merchant/billing/integrations/action_view_helper'
-- ActionView::Base.send(:include, ActiveMerchant::Billing::Integrations::ActionViewHelper)
+- require 'offsite_payments/action_view_helper'
+- ActionView::Base.send(:include, OffsitePayments::ActionViewHelper)
 
 = payment_service_for @payment.id, Settings.robokassa.login,
                         :amount => @payment.amount,
diff --git a/config/application.rb b/config/application.rb
index 3b37867b..e020c943 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -31,6 +31,6 @@ class Application < Rails::Application
     I18n.enforce_available_locales = true
 
     config.assets.precompile += %w[admin.js admin.scss]
-    config.active_record.raise_in_transactional_callbacks = true
+    # config.active_record.raise_in_transactional_callbacks = true
   end
 end
diff --git a/config/initializers/active_merchant.rb b/config/initializers/active_merchant.rb
index 13100852..0477e47a 100644
--- a/config/initializers/active_merchant.rb
+++ b/config/initializers/active_merchant.rb
@@ -1,8 +1,9 @@
 # frozen_string_literal: true
 
 require 'active_merchant'
-require 'active_merchant/billing/integrations/action_view_helper'
+require 'offsite_payments/action_view_helper'
 
-ActionView::Base.send(:include, ActiveMerchant::Billing::Integrations::ActionViewHelper)
+# https://github.com/activemerchant/active_merchant/issues/1397
+ActionView::Base.send(:include, OffsitePayments::ActionViewHelper)
 
-ActiveMerchant::Billing::Base.integration_mode = :production
+ActiveMerchant::Billing::Base.mode = :production
diff --git a/config/initializers/rails_config.rb b/config/initializers/rails_config.rb
index c109cd71..41dee6a1 100644
--- a/config/initializers/rails_config.rb
+++ b/config/initializers/rails_config.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
-RailsConfig.setup do |config|
+Config.setup do |config|
   config.const_name = 'Settings'
 end
diff --git a/spec/controllers/admin/change_languages_controller_spec.rb b/spec/controllers/admin/change_languages_controller_spec.rb
index 2d526829..4bc92517 100644
--- a/spec/controllers/admin/change_languages_controller_spec.rb
+++ b/spec/controllers/admin/change_languages_controller_spec.rb
@@ -8,7 +8,7 @@
   describe 'PUT #update' do
     before do
       request.env['HTTP_REFERER'] = 'where_i_came_from'
-      put :update, locale: :ru
+      put :update, params: { locale: :ru }
     end
 
     it 'session locale will be set to RU' do
diff --git a/spec/controllers/admin/connections_controller_spec.rb b/spec/controllers/admin/connections_controller_spec.rb
index b757bd61..3ec8ecf1 100644
--- a/spec/controllers/admin/connections_controller_spec.rb
+++ b/spec/controllers/admin/connections_controller_spec.rb
@@ -33,7 +33,7 @@
   describe 'GET #show' do
     let(:connection) { create(:connect) }
 
-    before { get :show, id: connection.id }
+    before { get :show, params: { id: connection.id } }
 
     it { is_expected.to be_success }
     it { is_expected.to render_template :show }
diff --git a/spec/controllers/admin/options_controller_spec.rb b/spec/controllers/admin/options_controller_spec.rb
index 4a3b3bd0..b26d42a8 100644
--- a/spec/controllers/admin/options_controller_spec.rb
+++ b/spec/controllers/admin/options_controller_spec.rb
@@ -26,12 +26,12 @@
 
       it 'creates new option' do
         expect do
-          post :create, option: attrs
+          post :create, params: { option: attrs }
         end.to change(Option.all, :count).by(1)
       end
 
       it 'redirects to options path' do
-        post :create, option: attrs
+        post :create, params: { option: attrs }
         expect(response).to redirect_to admin_options_path
       end
     end
@@ -40,7 +40,7 @@
       let(:attrs) { Hash[name: nil, code: nil] }
 
       it 'renders new form' do
-        post :create, option: attrs
+        post :create, params: { option: attrs }
         expect(response).to render_template :new
       end
     end
@@ -48,7 +48,7 @@
 
   describe 'GET #edit' do
     let(:option) { create(:option) }
-    before { get :edit, id: option.id }
+    before { get :edit, params: { id: option.id } }
 
     it { is_expected.to be_success }
     it { is_expected.to render_template :edit }
@@ -61,12 +61,12 @@
       let(:attrs) { Hash[name: 'new_name', code: 'new_code'] }
 
       it 'updates option' do
-        put :update, id: option.id, option: attrs
+        put :update, params: { id: option.id, option: attrs }
         expect(option.reload.name).to eq attrs[:name]
       end
 
       it 'redirects to options path' do
-        put :update, id: option.id, option: attrs
+        put :update, params: { id: option.id, option: attrs }
         expect(subject).to redirect_to admin_options_path
       end
     end
@@ -75,7 +75,7 @@
       let(:attrs) { Hash[code: nil] }
 
       it 'renders edit form' do
-        put :update, id: option.id, option: attrs
+        put :update, params: { id: option.id, option: attrs }
         expect(subject).to render_template :edit
       end
     end
diff --git a/spec/controllers/admin/pay_systems_controller_spec.rb b/spec/controllers/admin/pay_systems_controller_spec.rb
index b784ed0e..3c691441 100644
--- a/spec/controllers/admin/pay_systems_controller_spec.rb
+++ b/spec/controllers/admin/pay_systems_controller_spec.rb
@@ -36,7 +36,7 @@
 
     describe 'GET #show' do
       let!(:pay_system) { create :pay_system }
-      before { get :show, id: pay_system.id }
+      before { get :show, params: { id: pay_system.id } }
 
       it 'renders template' do
         expect(response).to render_template :show
@@ -65,12 +65,12 @@
 
         it 'creates new pay_system' do
           expect do
-            post :create, pay_system: attrs
+            post :create, params: { pay_system: attrs }
           end.to change(PaySystem, :count).by(1)
         end
 
         it 'redirects to pay_systems list' do
-          post :create, pay_system: attrs
+          post :create, params: { pay_system: attrs }
           expect(response).to redirect_to admin_pay_systems_path
         end
       end
@@ -79,7 +79,7 @@
         let(:attrs) { Hash[name: nil, code: nil] }
 
         it 'renders pay_system form' do
-          post :create, pay_system: attrs
+          post :create, params: { pay_system: attrs }
           expect(response).to render_template :new
         end
       end
@@ -89,7 +89,7 @@
       let!(:pay_system) { create(:pay_system) }
 
       it 'renders edit pay_system page' do
-        get :edit, id: pay_system.id
+        get :edit, params: { id: pay_system.id }
         expect(response).to render_template :edit
       end
     end
@@ -102,12 +102,12 @@
 
         it 'updates pay_system' do
           new_pay_system = create(:pay_system)
-          put :update, id: new_pay_system.id, pay_system: attrs
+          put :update, params: { id: new_pay_system.id, pay_system: attrs }
           expect(new_pay_system.reload.name).to eq attrs[:name]
         end
 
         it 'redirects to pay_systems list' do
-          put :update, id: pay_system.id, pay_system: attrs
+          put :update, params: { id: pay_system.id, pay_system: attrs }
           expect(response).to redirect_to admin_pay_systems_path
         end
       end
@@ -116,7 +116,7 @@
         let(:attrs) { Hash[name: nil] }
 
         it 'renders edit form' do
-          put :update, id: pay_system.id, pay_system: attrs
+          put :update, params: { id: pay_system.id, pay_system: attrs }
           expect(response).to render_template :edit
         end
       end
diff --git a/spec/controllers/admin/plans_controller_spec.rb b/spec/controllers/admin/plans_controller_spec.rb
index 56073074..2a629425 100644
--- a/spec/controllers/admin/plans_controller_spec.rb
+++ b/spec/controllers/admin/plans_controller_spec.rb
@@ -52,12 +52,12 @@
 
         it 'creates new plan' do
           expect do
-            post :create, plan: attrs
+            post :create, params: { plan: attrs }
           end.to change(Plan, :count).by(1)
         end
 
         it 'redirects to plans list' do
-          post :create, plan: attrs
+          post :create, params: { plan: attrs }
           expect(response).to redirect_to admin_plans_path
         end
       end
@@ -66,7 +66,7 @@
         let(:attrs) { Hash[name: nil, price: nil] }
 
         it 'renders plan form' do
-          post :create, plan: attrs
+          post :create, params: { plan: attrs }
           expect(response).to render_template :new
         end
       end
@@ -76,7 +76,7 @@
       let!(:plan) { create(:plan) }
 
       it 'renders edit plan page' do
-        get :edit, id: plan.id
+        get :edit, params: { id: plan.id }
         expect(response).to render_template :edit
       end
     end
@@ -89,12 +89,12 @@
 
         it 'updates plan' do
           new_plan = create(:plan)
-          put :update, id: new_plan.id, plan: attrs
+          put :update, params: { id: new_plan.id, plan: attrs }
           expect(new_plan.reload.name).to eq attrs[:name]
         end
 
         it 'redirects to plans list' do
-          put :update, id: plan.id, plan: attrs
+          put :update, params: { id: plan.id, plan: attrs }
           expect(response).to redirect_to admin_plans_path
         end
       end
@@ -103,7 +103,7 @@
         let(:attrs) { Hash[name: nil] }
 
         it 'renders edit form' do
-          put :update, id: plan.id, plan: attrs
+          put :update, params: { id: plan.id, plan: attrs }
           expect(response).to render_template :edit
         end
       end
@@ -114,7 +114,7 @@
 
       it 'removes plan' do
         expect do
-          delete :destroy, id: plan.id
+          delete :destroy, params: { id: plan.id }
         end.to change(Plan, :count).by(-1)
       end
     end
diff --git a/spec/controllers/admin/profiles_controller_spec.rb b/spec/controllers/admin/profiles_controller_spec.rb
index 7fa87ada..15c6f4dc 100644
--- a/spec/controllers/admin/profiles_controller_spec.rb
+++ b/spec/controllers/admin/profiles_controller_spec.rb
@@ -40,7 +40,7 @@
 
     describe 'PUT #update' do
       let!(:old_password) { admin.encrypted_password }
-      before { put :update, admin: params }
+      before { put :update, params: { admin: params } }
 
       context 'valid params' do
         let(:params) do
diff --git a/spec/controllers/admin/promos_controller_spec.rb b/spec/controllers/admin/promos_controller_spec.rb
index 860c580d..a7480366 100644
--- a/spec/controllers/admin/promos_controller_spec.rb
+++ b/spec/controllers/admin/promos_controller_spec.rb
@@ -36,13 +36,13 @@
         let(:attrs) { Hash[name: 'new name', type: 'withdrawal', promoter_type: 'discount'] }
 
         it 'redirects to promos path' do
-          post :create, promo: attrs
+          post :create, params: { promo: attrs }
           expect(subject).to redirect_to edit_admin_promo_path(Promo.last)
         end
 
         it 'creates new promo' do
           expect do
-            post :create, promo: attrs
+            post :create, params: { promo: attrs }
           end.to change(Promo, :count).by(1)
         end
       end
@@ -51,13 +51,13 @@
         let(:attrs) { Hash[name: nil] }
 
         it 'renders new template' do
-          post :create, promo: attrs
+          post :create, params: { promo: attrs }
           expect(subject).to render_template :new
         end
 
         it 'does not create promo' do
           expect do
-            post :create, promo: attrs
+            post :create, params: { promo: attrs }
           end.not_to change(Promo, :count)
         end
       end
@@ -65,7 +65,7 @@
 
     describe 'GET #edit' do
       let(:promo) { create(:promo) }
-      before { get :edit, id: promo.id }
+      before { get :edit, params: { id: promo.id } }
 
       it { is_expected.to render_template :edit }
       it { expect(subject.status).to eq 200 }
@@ -78,12 +78,12 @@
         let(:attrs) { Hash[name: 'new name', type: 'withdrawal', promoter_type: 'discount'] }
 
         it 'redirects to edit page' do
-          put :update, promo: attrs, id: promo.id
+          put :update, params: { promo: attrs, id: promo.id }
           expect(subject).to redirect_to edit_admin_promo_path(promo)
         end
 
         it 'updates promo' do
-          put :update, promo: attrs, id: promo.id
+          put :update, params: { promo: attrs, id: promo.id }
           expect(promo.reload.name).to eq attrs[:name]
         end
       end
@@ -92,12 +92,12 @@
         let(:attrs) { Hash[name: 'new name', type: nil, promoter_type: 'discount'] }
 
         it 'renders edit form' do
-          put :update, promo: attrs, id: promo.id
+          put :update, params: { promo: attrs, id: promo.id }
           expect(subject).to render_template :edit
         end
 
         it 'does not update promo' do
-          put :update, promo: attrs, id: promo.id
+          put :update, params: { promo: attrs, id: promo.id }
           expect(promo.reload.name).not_to eq attrs[:name]
         end
       end
diff --git a/spec/controllers/admin/servers_controller_spec.rb b/spec/controllers/admin/servers_controller_spec.rb
index d9170ca0..88189d2b 100644
--- a/spec/controllers/admin/servers_controller_spec.rb
+++ b/spec/controllers/admin/servers_controller_spec.rb
@@ -36,7 +36,7 @@
 
     describe 'GET #show' do
       let!(:server) { create :server }
-      before { get :show, id: server.id }
+      before { get :show, params: { id: server.id } }
 
       it 'renders template' do
         expect(response).to render_template :show
@@ -65,12 +65,12 @@
 
         it 'creates new server' do
           expect do
-            post :create, server: attrs
+            post :create, params: { server: attrs }
           end.to change(Server, :count).by(1)
         end
 
         it 'redirects to servers list' do
-          post :create, server: attrs
+          post :create, params: { server: attrs }
           expect(response).to redirect_to admin_servers_path
         end
       end
@@ -79,7 +79,7 @@
         let(:attrs) { Hash[hostname: nil, ip_address: nil] }
 
         it 'renders server form' do
-          post :create, server: attrs
+          post :create, params: { server: attrs }
           expect(response).to render_template :new
         end
       end
@@ -89,7 +89,7 @@
       let!(:server) { create(:server) }
 
       it 'renders edit server page' do
-        get :edit, id: server.id
+        get :edit, params: { id: server.id }
         expect(response).to render_template :edit
       end
     end
@@ -102,12 +102,12 @@
 
         it 'updates server' do
           new_server = create(:server)
-          put :update, id: new_server.id, server: attrs
+          put :update, params: { id: new_server.id, server: attrs }
           expect(new_server.reload.hostname).to eq attrs[:hostname]
         end
 
         it 'redirects to servers list' do
-          put :update, id: server.id, server: attrs
+          put :update, params: { id: server.id, server: attrs }
           expect(response).to redirect_to admin_servers_path
         end
       end
@@ -116,7 +116,7 @@
         let(:attrs) { Hash[hostname: nil] }
 
         it 'renders edit form' do
-          put :update, id: server.id, server: attrs
+          put :update, params: { id: server.id, server: attrs }
           expect(response).to render_template :edit
         end
       end
@@ -127,7 +127,7 @@
 
       it 'removes server' do
         expect do
-          delete :destroy, id: server.id
+          delete :destroy, params: { id: server.id }
         end.to change(Server, :count).by(-1)
       end
     end
@@ -138,11 +138,11 @@
 
       it 'calls config builder' do
         allow_any_instance_of(ServerConfigBuilder).to receive(:to_text).and_return(config)
-        get :generate_config, id: server.id
+        get :generate_config, params: { id: server.id }
       end
 
       it 'sends config to download' do
-        get :generate_config, id: server.id
+        get :generate_config, params: { id: server.id }
         expect(response.header['Content-Type']).to eq 'application/octet-stream'
       end
     end
diff --git a/spec/controllers/admin/users_controller_spec.rb b/spec/controllers/admin/users_controller_spec.rb
index c6a267fa..ef9daaea 100644
--- a/spec/controllers/admin/users_controller_spec.rb
+++ b/spec/controllers/admin/users_controller_spec.rb
@@ -30,7 +30,7 @@
 
   describe 'GET #show' do
     let(:user) { create(:user) }
-    before { get :show, id: user.id }
+    before { get :show, params: { id: user.id } }
 
     it { is_expected.to be_success }
     it { is_expected.to render_template :show }
@@ -38,7 +38,7 @@
 
   describe 'GET #edit' do
     let(:user) { create(:user) }
-    before { get :edit, id: user.id }
+    before { get :edit, params: { id: user.id } }
 
     it { is_expected.to be_success }
     it { is_expected.to render_template :edit }
@@ -69,12 +69,12 @@
 
       it 'run operation' do
         expect(operation).to receive(:call).and_return(success: true, user: user)
-        post :create, user: params
+        post :create, params: { user: params }
       end
 
       it 'redirects to users path' do
         allow(operation).to receive(:call).and_return(success: true, user: user)
-        post :create, user: params
+        post :create, params: { user: params }
         expect(subject).to redirect_to admin_users_path
       end
     end
@@ -91,12 +91,12 @@
 
       it 'run operation' do
         expect(operation).to receive(:call).and_return(success: false, user: user)
-        post :create, user: params
+        post :create, params: { user: params }
       end
 
       it 'redirects to users path' do
         allow(operation).to receive(:call).and_return(success: false, user: user)
-        post :create, user: params
+        post :create, params: { user: params }
         expect(subject).to render_template :new
       end
     end
@@ -105,7 +105,7 @@
   describe 'PUT #update' do
     let(:user) { create(:user) }
 
-    before { put :update, id: user.id, user: attrs }
+    before { put :update, params: { id: user.id, user: attrs } }
 
     context 'params correct' do
       let(:attrs) { Hash[email: 'new@mail.ru'] }
@@ -129,7 +129,7 @@
 
     it 'creates new withdrawal' do
       expect do
-        put :withdraw, id: user.id
+        put :withdraw, params: { id: user.id }
       end.to change(Withdrawal, :count).by(1)
     end
   end
@@ -141,18 +141,18 @@
 
     it 'creates new withdrawal prolongation' do
       expect do
-        put :prolongate, id: user.id, withdrawal_prolongation: attrs
+        put :prolongate, params: { id: user.id, withdrawal_prolongation: attrs }
       end.to change(WithdrawalProlongation, :count).by(1)
     end
 
     it 'prolongation is created for last withdrawal' do
       expect do
-        put :prolongate, id: user.id, withdrawal_prolongation: attrs
+        put :prolongate, params: { id: user.id, withdrawal_prolongation: attrs }
       end.to change(user.withdrawals.last.withdrawal_prolongations, :count).by(1)
     end
 
     it 'prolongation days number equals form data' do
-      put :prolongate, id: user.id, withdrawal_prolongation: attrs
+      put :prolongate, params: { id: user.id, withdrawal_prolongation: attrs }
       expect(user.withdrawals.last.withdrawal_prolongations.last.days_number).to eq attrs[:days_number]
     end
   end
@@ -164,12 +164,12 @@
 
     it 'creates new payment' do
       expect do
-        put :payment, id: user.id, payment: attrs
+        put :payment, params: { id: user.id, payment: attrs }
       end.to change(Payment, :count).by(1)
     end
 
     context 'after request' do
-      before { put :payment, id: user.id, payment: attrs }
+      before { put :payment, params: { id: user.id, payment: attrs } }
 
       it 'payment is accepted' do
         expect(Payment.last.accepted?).to be true
@@ -203,19 +203,19 @@
     let(:user) { create(:user) }
 
     it 'calles enable action' do
-      put :enable_test_period, id: user.id
+      put :enable_test_period, params: { id: user.id }
       expect(user.reload.test_period.enabled?).to be true
     end
 
     it 'send email' do
       allow_any_instance_of(User).to receive(:test_period_started_at).and_return(Date.current)
       expect do
-        put :enable_test_period, id: user.id
+        put :enable_test_period, params: { id: user.id }
       end.to change(ActionMailer::Base.deliveries, :size).by(1)
     end
 
     it 'redirects to user path' do
-      put :enable_test_period, id: user.id
+      put :enable_test_period, params: { id: user.id }
       expect(response).to redirect_to admin_user_path(user)
     end
   end
@@ -225,11 +225,11 @@
 
     it 'calles disable action' do
       allow_any_instance_of(TestPeriod).to receive(:disable!)
-      put :disable_test_period, id: user.id
+      put :disable_test_period, params: { id: user.id }
     end
 
     it 'redirects to user path' do
-      put :disable_test_period, id: user.id
+      put :disable_test_period, params: { id: user.id }
       expect(response).to redirect_to admin_user_path(user)
     end
   end
@@ -239,11 +239,11 @@
 
     it 'calls disconnector' do
       allow_any_instance_of(ForcedDisconnect).to receive(:invoke)
-      put :force_disconnect, id: user.id
+      put :force_disconnect, params: { id: user.id }
     end
 
     it 'redirects to user path' do
-      put :force_disconnect, id: user.id
+      put :force_disconnect, params: { id: user.id }
       expect(response).to redirect_to admin_user_path(user)
     end
   end
diff --git a/spec/controllers/api/authentication_controller_spec.rb b/spec/controllers/api/authentication_controller_spec.rb
index 6bc4d1cf..67f6fccb 100644
--- a/spec/controllers/api/authentication_controller_spec.rb
+++ b/spec/controllers/api/authentication_controller_spec.rb
@@ -19,7 +19,7 @@
       before { create(:withdrawal, user: user) }
 
       it 'returns 200 status' do
-        post :auth, params
+        post :auth, params: params
         expect(response.status).to eq 200
       end
     end
@@ -28,7 +28,7 @@
       let(:params) { Hash[login: user.vpn_login, password: 'asd', hostname: server.hostname] }
 
       it 'returns 404 status' do
-        post :auth, params
+        post :auth, params: params
         expect(response.status).to eq 404
       end
     end
diff --git a/spec/controllers/api/connection_controller_spec.rb b/spec/controllers/api/connection_controller_spec.rb
index caced7cd..140f14ae 100644
--- a/spec/controllers/api/connection_controller_spec.rb
+++ b/spec/controllers/api/connection_controller_spec.rb
@@ -19,13 +19,13 @@
     describe 'POST #connect' do
       it 'calls connector' do
         allow_any_instance_of(Connector).to receive(:invoke).once
-        post :connect, attrs
+        post :connect, params: attrs
       end
 
       it 'passed connect action to connector' do
         connector = Connector.new(attrs.merge!(action: 'connect'))
         expect(Connector).to receive(:new).with(attrs).and_return(connector)
-        post :connect, attrs
+        post :connect, params: attrs
       end
 
       context 'user has options' do
@@ -35,7 +35,7 @@
           option = create(:active_option)
           user.plan.options << option
           user.options << option
-          post :connect, params
+          post :connect, params: params
         end
 
         it { is_expected.to be_json }
@@ -49,13 +49,13 @@
     describe 'POST #disconnect' do
       it 'calls connector' do
         allow_any_instance_of(Connector).to receive(:invoke).once
-        post :disconnect, attrs
+        post :disconnect, params: attrs
       end
 
       it 'passed disconnect action to connector' do
         connector = Connector.new(attrs.merge!(action: 'disconnect'))
         expect(Connector).to receive(:new).with(attrs).and_return(connector)
-        post :disconnect, attrs
+        post :disconnect, params: attrs
       end
     end
   end
diff --git a/spec/controllers/api/servers_controller_spec.rb b/spec/controllers/api/servers_controller_spec.rb
index dbc9c1ae..4a112b3e 100644
--- a/spec/controllers/api/servers_controller_spec.rb
+++ b/spec/controllers/api/servers_controller_spec.rb
@@ -23,7 +23,7 @@
 
       it 'raises error' do
         expect do
-          post :activate, params
+          post :activate, params: params
         end.to raise_error ApiException, "Server already exists: #{server}"
       end
     end
@@ -33,22 +33,22 @@
         let(:server) { Server.last }
 
         it 'renders json with auth key' do
-          post :activate, params
+          post :activate, params: params
           expect(response.body).to eq Hash[auth_key: server.auth_key].to_json
         end
 
         it 'returns success status' do
-          post :activate, params
+          post :activate, params: params
           expect(response.status).to eq 200
         end
 
         it 'updates server pki fields' do
-          expect { post :activate, params }
+          expect { post :activate, params: params }
             .to change { Server.count }.by(1)
         end
 
         it 'assigns certificate data to server' do
-          post :activate, params
+          post :activate, params: params
           expect(server.server_crt).to eq('server crt')
           expect(server.client_crt).to eq('client crt')
           expect(server.client_key).to eq('client key')
@@ -61,7 +61,7 @@
 
         it 'raises error' do
           expect do
-            post :activate, params
+            post :activate, params: params
           end.to raise_error ApiException, "Server activation attempt with incorrect token: #{signature}"
         end
       end
diff --git a/spec/controllers/billing/options_controller_spec.rb b/spec/controllers/billing/options_controller_spec.rb
index 5e455a41..8f3b4edd 100644
--- a/spec/controllers/billing/options_controller_spec.rb
+++ b/spec/controllers/billing/options_controller_spec.rb
@@ -18,7 +18,7 @@
 
     before do
       allow(Option::Activator).to receive(:run).with(@user, option_code).and_return(activation_result)
-      post :create, code: option_code
+      post :create, params: { code: option_code }
     end
 
     context 'success' do
@@ -52,7 +52,7 @@
     let(:new_attrs) { Hash[country: 'Russia'] }
     let!(:user_option) { create(:user_option, state: 'enabled', attrs: old_attrs, user: @user, option: option) }
 
-    before { put :update, id: option.id, option_attributes: new_attrs }
+    before { put :update, params: { id: option.id, option_attributes: new_attrs } }
 
     it 'changes attributes' do
       expect(user_option.reload.attrs['country']).to eq 'Russia'
@@ -65,7 +65,7 @@
 
     it 'calles toggle! on option' do
       allow_any_instance_of(UserOption).to receive(:toggle!)
-      put :toggle, id: option.id
+      put :toggle, params: { id: option.id }
     end
   end
 end
diff --git a/spec/controllers/billing/payments_controller_spec.rb b/spec/controllers/billing/payments_controller_spec.rb
index 76efd411..d25301a0 100644
--- a/spec/controllers/billing/payments_controller_spec.rb
+++ b/spec/controllers/billing/payments_controller_spec.rb
@@ -20,12 +20,12 @@
     end
 
     it 'displays new payment form' do
-      get :new, code: pay_system.code
+      get :new, params: { code: pay_system.code }
       expect(response).to render_template :new
     end
 
     it 'redirects to merchant form page on payment create' do
-      post :create, payment: attributes_for(:payment).merge!(pay_system_id: pay_system.id)
+      post :create, params: { payment: attributes_for(:payment).merge!(pay_system_id: pay_system.id) }
       expect(response).to redirect_to merchant_billing_payment_path(Payment.last)
     end
 
@@ -36,7 +36,7 @@
       end
 
       it 'redirects to pay systems list' do
-        get :merchant, id: @payment.id
+        get :merchant, params: { id: @payment.id }
         expect(response).to redirect_to billing_payments_path
       end
     end
diff --git a/spec/controllers/billing/promotions_controller_spec.rb b/spec/controllers/billing/promotions_controller_spec.rb
index ce452b27..6e0a7b3d 100644
--- a/spec/controllers/billing/promotions_controller_spec.rb
+++ b/spec/controllers/billing/promotions_controller_spec.rb
@@ -10,7 +10,7 @@
   describe 'POST #create' do
     context 'when not authorized' do
       it 'does not respond' do
-        post :create, promo: { code: promo_code }
+        post :create, params: { promo: { code: promo_code } }
         expect(subject).to redirect_to new_user_session_path
       end
     end
@@ -20,7 +20,7 @@
 
       context 'promo with such code does not exist' do
         before do
-          post :create, promotion: { promo_code: promo_code }
+          post :create, params: { promotion: { promo_code: promo_code } }
         end
 
         it 'redirects to settings page' do
@@ -37,7 +37,7 @@
         let!(:promotion) { create(:promotion, user: User.last, promo: promo) }
 
         before do
-          post :create, promotion: { promo_code: promo_code }
+          post :create, params: { promotion: { promo_code: promo_code } }
         end
 
         it 'redirects to settings page' do
@@ -51,7 +51,7 @@
 
       context 'promo exists, promotion not' do
         let!(:promo) { create(:active_promo, date_from: 1.week.ago, date_to: 1.week.from_now, promo_code: promo_code) }
-        before { post :create, promotion: { promo_code: promo_code } }
+        before { post :create, params: { promotion: { promo_code: promo_code } } }
 
         it 'redirects to settings page' do
           expect(subject).to redirect_to settings_path
diff --git a/spec/controllers/billing/robokassa_controller_spec.rb b/spec/controllers/billing/robokassa_controller_spec.rb
index f96c864a..9505cdc0 100644
--- a/spec/controllers/billing/robokassa_controller_spec.rb
+++ b/spec/controllers/billing/robokassa_controller_spec.rb
@@ -15,7 +15,7 @@
 
       it 'raises error' do
         expect do
-          post :result, attrs
+          post :result, params: attrs
         end.to raise_error 'Invalid robokassa notification'
       end
     end
@@ -25,11 +25,11 @@
       let(:attrs) { Hash['OutSum' => '9.99', 'InvId' => '10', 'SignatureValue' => 'D25F8F107E3482EF3CCAFC620CC8BA3E'] }
 
       before do
-        allow_any_instance_of(ActiveMerchant::Billing::Integrations::Robokassa::Notification)
+        allow_any_instance_of(OffsitePayments::Integrations::Robokassa::Notification)
           .to receive(:acknowledge)
           .and_return(true)
         allow(Payment).to receive(:find).and_return(payment)
-        post :result, attrs
+        post :result, params: attrs
       end
 
       it 'returns 200 state' do
diff --git a/spec/controllers/billing/servers_controller_spec.rb b/spec/controllers/billing/servers_controller_spec.rb
index 0dea13ca..bc607f61 100644
--- a/spec/controllers/billing/servers_controller_spec.rb
+++ b/spec/controllers/billing/servers_controller_spec.rb
@@ -22,11 +22,11 @@
 
     it 'calls config builder' do
       allow_any_instance_of(ServerConfigBuilder).to receive(:to_text).and_return(config)
-      get :download_config, id: server.id
+      get :download_config, params: { id: server.id }
     end
 
     it 'sends config to download' do
-      get :download_config, id: server.id
+      get :download_config, params: { id: server.id }
       expect(response.header['Content-Type']).to eq 'application/octet-stream'
     end
   end
diff --git a/spec/controllers/billing/webmoney_controller_spec.rb b/spec/controllers/billing/webmoney_controller_spec.rb
index 04e7df24..629a6785 100644
--- a/spec/controllers/billing/webmoney_controller_spec.rb
+++ b/spec/controllers/billing/webmoney_controller_spec.rb
@@ -14,7 +14,7 @@
       context 'key param is not present' do
         let(:attrs) { Hash[] }
 
-        before { post :result, attrs }
+        before { post :result, params: attrs }
 
         it 'renders YES text' do
           expect(subject.body).to include 'YES'
@@ -28,7 +28,7 @@
 
         it 'raises error' do
           expect do
-            post :result, attrs
+            post :result, params: attrs
           end.to raise_error 'Undefined transaction_item_id'
         end
       end
@@ -39,7 +39,7 @@
 
         it 'raises error' do
           expect do
-            post :result, attrs
+            post :result, params: attrs
           end.to raise_error 'Invalid webmoney verification key'
         end
       end
@@ -64,14 +64,14 @@
         end
 
         before do
-          allow_any_instance_of(ActiveMerchant::Billing::Integrations::Webmoney::Notification)
+          allow_any_instance_of(OffsitePayments::Integrations::Webmoney::Notification)
             .to receive(:recognizes?)
             .and_return(true)
-          allow_any_instance_of(ActiveMerchant::Billing::Integrations::Webmoney::Notification)
+          allow_any_instance_of(OffsitePayments::Integrations::Webmoney::Notification)
             .to receive(:acknowledge)
             .and_return(true)
           allow(Payment).to receive(:find).and_return(payment)
-          post :result, attrs
+          post :result, params: attrs
         end
 
         it 'returns 200 state' do
diff --git a/spec/controllers/referrers_controller_spec.rb b/spec/controllers/referrers_controller_spec.rb
index baf5c682..f7259096 100644
--- a/spec/controllers/referrers_controller_spec.rb
+++ b/spec/controllers/referrers_controller_spec.rb
@@ -5,7 +5,7 @@
 describe ReferrersController do
   describe 'GET #set_referrer' do
     let(:user) { create(:user) }
-    before { get :set_referrer, code: user.reflink }
+    before { get :set_referrer, params: { code: user.reflink } }
 
     it 'sets reflink to cookie' do
       expect(response.cookies['reflink']).to eq user.reflink
diff --git a/spec/controllers/users/registrations_controller_spec.rb b/spec/controllers/users/registrations_controller_spec.rb
index bd98796a..34b65960 100644
--- a/spec/controllers/users/registrations_controller_spec.rb
+++ b/spec/controllers/users/registrations_controller_spec.rb
@@ -13,7 +13,7 @@
     context 'reflink set in params' do
       before do
         request.cookies['reflink'] = referrer.reflink
-        post :create, user: attrs
+        post :create, params: { user: attrs }
       end
 
       it 'creates user' do
@@ -31,7 +31,7 @@
 
     context 'no reflink in params' do
       before do
-        post :create, user: attrs
+        post :create, params: { user: attrs }
       end
 
       it 'creates user' do
diff --git a/spec/features/admin/users/manual_payment_spec.rb b/spec/features/admin/users/manual_payment_spec.rb
index 932b7f4b..bfee6458 100644
--- a/spec/features/admin/users/manual_payment_spec.rb
+++ b/spec/features/admin/users/manual_payment_spec.rb
@@ -21,7 +21,7 @@
       click_button I18n.t('global.apply')
     end
 
-    expect(page.find('p.user_balance')).to have_content (amount - user.plan.price)
+    expect(page.find('.user_balance')).to have_content (amount - user.plan.price)
     expect(page).to have_content I18n.t('admin.users.notices.payment_created')
   end
 end
diff --git a/spec/mailers/user_connection_config_mailer_spec.rb b/spec/mailers/user_connection_config_mailer_spec.rb
index 0c763a91..31dcd70f 100644
--- a/spec/mailers/user_connection_config_mailer_spec.rb
+++ b/spec/mailers/user_connection_config_mailer_spec.rb
@@ -7,9 +7,14 @@
     subject { described_class.notify(user: user) }
     let!(:user) { create(:user) }
     let!(:server) { create(:server) }
-    let!(:plan) { create(:plan, users: [user], servers: [server]) }
+    let!(:plan) { create(:plan) }
     let(:server_config) { ServerConfigBuilder.new(server: server).to_text }
 
+    before do
+      plan.users << user
+      plan.servers << server
+    end
+
     its(:subject) { is_expected.to eq I18n.t('mailers.user_connection_config_mailer.subject') }
     its(:to) { is_expected.to eq [user.email] }
     its(:from) { is_expected.to eq [ENV['EMAIL_FROM']] }
diff --git a/spec/models/withdrawal_spec.rb b/spec/models/withdrawal_spec.rb
index af985b93..1f008e2f 100644
--- a/spec/models/withdrawal_spec.rb
+++ b/spec/models/withdrawal_spec.rb
@@ -3,7 +3,7 @@
 require 'spec_helper'
 
 describe Withdrawal do
-  subject { build(:withdrawal) }
+  subject { create(:withdrawal) }
 
   it { is_expected.to be_valid }
   it { is_expected.to validate_presence_of(:plan_id) }
diff --git a/spec/services/newsletter_manager_spec.rb b/spec/services/newsletter_manager_spec.rb
index edb3755b..803e6b70 100644
--- a/spec/services/newsletter_manager_spec.rb
+++ b/spec/services/newsletter_manager_spec.rb
@@ -12,7 +12,7 @@
       let(:list_name) { :all }
 
       it 'calls Mailchimp api' do
-        ::FakeWeb.register_uri(:post, 'https://key.api.mailchimp.com/2.0/lists/subscribe', body: '{}')
+        FakeWeb.register_uri(:post, 'https://key.api.mailchimp.com/2.0/lists/subscribe', body: '{}')
         subject.add_to_list(email, list_name)
       end
     end
diff --git a/spec/services/referrer/rewarder_spec.rb b/spec/services/referrer/rewarder_spec.rb
index ed18d9d0..491b6168 100644
--- a/spec/services/referrer/rewarder_spec.rb
+++ b/spec/services/referrer/rewarder_spec.rb
@@ -40,7 +40,7 @@
 
   context 'withdrawal invalid' do
     let(:user) { create(:user) }
-    let(:withdrawal) { Withdrawal.create(user: user) }
+    let(:withdrawal) { Withdrawal.create(user: user, amount: 0) }
 
     it 'does not create reward' do
       expect do
diff --git a/spec/shared_examples/admin_controller_access_spec_shared.rb b/spec/shared_examples/admin_controller_access_spec_shared.rb
index 4e71fbf8..bb1b5101 100644
--- a/spec/shared_examples/admin_controller_access_spec_shared.rb
+++ b/spec/shared_examples/admin_controller_access_spec_shared.rb
@@ -5,7 +5,7 @@
     login_user
 
     it 'does not allow to be accessed by user' do
-      send(method, action, params)
+      send(method, action, params: params)
       expect(response).to redirect_to new_admin_session_path
     end
   end
diff --git a/spec/shared_examples/api_call_controller_validation_shared.rb b/spec/shared_examples/api_call_controller_validation_shared.rb
index 8d74371c..80fc9a83 100644
--- a/spec/shared_examples/api_call_controller_validation_shared.rb
+++ b/spec/shared_examples/api_call_controller_validation_shared.rb
@@ -12,7 +12,7 @@
 
         it 'raises error' do
           expect do
-            post action, attrs
+            post action, params: attrs
           end.to raise_error ApiException, 'Server not found'
         end
       end
@@ -22,7 +22,7 @@
       context 'when pending' do
         it 'raises error' do
           expect do
-            post action, attrs
+            post action, params: attrs
           end.to raise_error ApiException, 'Server not active'
         end
       end
@@ -32,7 +32,7 @@
 
         it 'raises error' do
           expect do
-            post action, attrs
+            post action, params: attrs
           end.to raise_error ApiException, 'Server not active'
         end
       end
@@ -51,7 +51,7 @@
 
         it 'raises error' do
           expect do
-            post action, attrs
+            post action, params: attrs
           end.to raise_error ApiException, 'Invalid api call'
         end
       end
diff --git a/spec/shared_examples/validates_paysystem_enabled_shared.rb b/spec/shared_examples/validates_paysystem_enabled_shared.rb
index afc11873..7ca7ada3 100644
--- a/spec/shared_examples/validates_paysystem_enabled_shared.rb
+++ b/spec/shared_examples/validates_paysystem_enabled_shared.rb
@@ -8,7 +8,7 @@
 
       it 'raises error' do
         expect do
-          post action, payment_id_key => payment.id
+          post action, params: { payment_id_key => payment.id }
         end.to raise_error BillingException
       end
     end
diff --git a/spec/workers/create_user_mail_worker_spec.rb b/spec/workers/create_user_mail_worker_spec.rb
index a410df0e..09c88215 100644
--- a/spec/workers/create_user_mail_worker_spec.rb
+++ b/spec/workers/create_user_mail_worker_spec.rb
@@ -8,9 +8,14 @@
   context '#perform' do
     let(:user) { create(:user) }
     let(:server) { create(:server) }
-    let!(:plan) { create(:plan, users: [user], servers: [server]) }
+    let!(:plan) { create(:plan) }
     let(:mailer) { double }
 
+    before do
+      plan.users << user
+      plan.servers << server
+    end
+
     it 'notifies user by email' do
       expect { subject.perform(user.id) }.to change(ActionMailer::Base.deliveries, :count).by(1)
     end