diff --git a/Gemfile b/Gemfile
index 4239d7f7..0bf0d832 100644
--- a/Gemfile
+++ b/Gemfile
@@ -89,7 +89,7 @@ group :development do
 end
 
 group :development, :test do
-  gem 'rubocop', '1.50.2', require: false
+  gem 'rubocop', require: false
   gem 'rubocop-rails', require: false
   gem 'rubocop-rspec', require: false
   gem 'ruby-prof', require: false
diff --git a/Gemfile.lock b/Gemfile.lock
index 72a3eff2..4c2d9a37 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -316,10 +316,9 @@ GEM
     nokogiri (1.13.1)
       mini_portile2 (~> 2.7.0)
       racc (~> 1.4)
-    parallel (1.24.0)
-    parser (3.3.0.2)
+    parallel (1.21.0)
+    parser (3.1.0.0)
       ast (~> 2.4.1)
-      racc
     pdf-core (0.9.0)
     polyglot (0.3.5)
     prawn (2.4.0)
@@ -401,7 +400,7 @@ GEM
     redis-namespace (1.8.1)
       redis (>= 3.0.4)
     ref (2.0.0)
-    regexp_parser (2.9.0)
+    regexp_parser (2.2.1)
     responders (3.0.1)
       actionpack (>= 5.0)
       railties (>= 5.0)
@@ -411,7 +410,7 @@ GEM
       redis-namespace (~> 1.6)
       sinatra (>= 0.9.2)
       vegas (~> 0.1.2)
-    rexml (3.2.6)
+    rexml (3.2.5)
     roo (2.8.3)
       nokogiri (~> 1)
       rubyzip (>= 1.3.0, < 3.0.0)
@@ -442,18 +441,17 @@ GEM
     rspec-rerun (1.1.0)
       rspec (~> 3.0)
     rspec-support (3.11.0)
-    rubocop (1.50.2)
-      json (~> 2.3)
+    rubocop (1.25.1)
       parallel (~> 1.10)
-      parser (>= 3.2.0.0)
+      parser (>= 3.1.0.0)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.8, < 3.0)
-      rexml (>= 3.2.5, < 4.0)
-      rubocop-ast (>= 1.28.0, < 2.0)
+      rexml
+      rubocop-ast (>= 1.15.1, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.30.0)
-      parser (>= 3.2.1.0)
+      unicode-display_width (>= 1.4.0, < 3.0)
+    rubocop-ast (1.15.2)
+      parser (>= 3.0.1.1)
     rubocop-rails (2.13.2)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
@@ -463,7 +461,7 @@ GEM
     ruby-filemagic (0.7.3)
     ruby-ole (1.2.12.2)
     ruby-prof (1.4.3)
-    ruby-progressbar (1.13.0)
+    ruby-progressbar (1.11.0)
     ruby-units (2.3.2)
     ruby2_keywords (0.0.5)
     ruby_parser (3.18.1)
@@ -542,7 +540,7 @@ GEM
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.8)
-    unicode-display_width (2.5.0)
+    unicode-display_width (2.1.0)
     uniform_notifier (1.14.2)
     vegas (0.1.11)
       rack (>= 1.0.0)
@@ -634,7 +632,7 @@ DEPENDENCIES
   rspec-core
   rspec-rails
   rspec-rerun
-  rubocop (= 1.50.2)
+  rubocop
   rubocop-rails
   rubocop-rspec
   ruby-filemagic
diff --git a/app/controllers/concerns/locale.rb b/app/controllers/concerns/locale.rb
index 794d7c24..22686c15 100644
--- a/app/controllers/concerns/locale.rb
+++ b/app/controllers/concerns/locale.rb
@@ -18,7 +18,7 @@ def session_language
   end
 
   def browser_language
-    request.env['HTTP_ACCEPT_LANGUAGE']&.scan(/^[a-z]{2}/)&.first
+    request.env['HTTP_ACCEPT_LANGUAGE'] ? request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first : nil
   end
 
   def default_language
diff --git a/app/controllers/sessions_controller.rb b/app/controllers/sessions_controller.rb
index 42769f08..5b3d0780 100644
--- a/app/controllers/sessions_controller.rb
+++ b/app/controllers/sessions_controller.rb
@@ -3,7 +3,9 @@ class SessionsController < ApplicationController
   layout 'login'
 
   def new
-    respond_to(&:html)
+    respond_to do |format|
+      format.html
+    end
   end
 
   def create
diff --git a/app/models/article.rb b/app/models/article.rb
index 001180ea..46aeb014 100644
--- a/app/models/article.rb
+++ b/app/models/article.rb
@@ -101,7 +101,7 @@ def in_open_order
     @in_open_order ||= begin
       order_articles = OrderArticle.where(order_id: Order.open.collect(&:id))
       order_article = order_articles.detect { |oa| oa.article_version.article_id == id }
-      order_article&.order
+      order_article ? order_article.order : nil
     end
   end
 
diff --git a/app/models/article_version.rb b/app/models/article_version.rb
index 50cf1b37..fbe08d89 100644
--- a/app/models/article_version.rb
+++ b/app/models/article_version.rb
@@ -138,7 +138,7 @@ def duplicate_including_article_unit_ratios
   # @return [Hash<Symbol, Object>] Changed attributes with new values
   def self.compare_attributes(attributes)
     unequal_attributes = attributes.select { |_name, values| values[0] != values[1] && !(values[0].blank? && values[1].blank?) }
-    unequal_attributes.to_a.to_h { |a| [a[0], a[1].last] }
+    unequal_attributes.to_a.map { |a| [a[0], a[1].last] }.to_h
   end
 
   protected
diff --git a/app/models/group_order_article.rb b/app/models/group_order_article.rb
index 4d74bab4..c00208ab 100644
--- a/app/models/group_order_article.rb
+++ b/app/models/group_order_article.rb
@@ -64,14 +64,14 @@ def update_quantities(quantity, tolerance)
         logger.debug("Need to decrease quantities for GroupOrderArticleQuantity[#{quantities[i].id}]")
         if (quantity < self.quantity && quantities[i].quantity > 0)
           delta = self.quantity - quantity
-          delta = [delta, quantities[i].quantity].min
+          delta = (delta > quantities[i].quantity ? quantities[i].quantity : delta)
           logger.debug("Decreasing quantity by #{delta}")
           quantities[i].quantity -= delta
           self.quantity -= delta
         end
         if (tolerance < self.tolerance && quantities[i].tolerance > 0)
           delta = self.tolerance - tolerance
-          delta = [delta, quantities[i].tolerance].min
+          delta = (delta > quantities[i].tolerance ? quantities[i].tolerance : delta)
           logger.debug("Decreasing tolerance by #{delta}")
           quantities[i].tolerance -= delta
           self.tolerance -= delta
diff --git a/config/environments/production.rb b/config/environments/production.rb
index ab83a4f6..0560b38d 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -98,7 +98,7 @@
   end
 
   # Use default logging formatter so that PID and timestamp are not suppressed.
-  config.log_formatter = Logger::Formatter.new
+  config.log_formatter = ::Logger::Formatter.new
 
   # Use a different logger for distributed setups.
   # require 'syslog/logger'
diff --git a/config/initializers/currency_display.rb b/config/initializers/currency_display.rb
index 71d108d2..7caa6a64 100644
--- a/config/initializers/currency_display.rb
+++ b/config/initializers/currency_display.rb
@@ -1,7 +1,7 @@
 # remove all currency translations, so that we can set the default language and
 # have it shown in all other languages too
-I18n.available_locales.each do |locale|
-  unless locale == I18n.default_locale
-    I18n.backend.store_translations(locale, number: { currency: { format: { unit: nil } } })
+::I18n.available_locales.each do |locale|
+  unless locale == ::I18n.default_locale
+    ::I18n.backend.store_translations(locale, number: { currency: { format: { unit: nil } } })
   end
 end
diff --git a/config/initializers/secret_token.rb b/config/initializers/secret_token.rb
index 6d310e32..14054341 100644
--- a/config/initializers/secret_token.rb
+++ b/config/initializers/secret_token.rb
@@ -5,7 +5,7 @@
 # Make sure the secret is at least 30 characters and all random,
 # no regular words or you'll be exposed to dictionary attacks.
 Foodsoft::Application.config.secret_key_base = begin
-  if (token = ENV.fetch('SECRET_KEY_BASE', nil)).present?
+  if (token = ENV['SECRET_KEY_BASE']).present?
     token
   elsif Rails.env.production? || Rails.env.staging?
     raise "You must set SECRET_KEY_BASE"
diff --git a/lib/apple_bar.rb b/lib/apple_bar.rb
index 81d1a1ea..a2176ea3 100644
--- a/lib/apple_bar.rb
+++ b/lib/apple_bar.rb
@@ -26,7 +26,7 @@ def group_bar_state
 
   # Use apples as percentage, but show at least 10 percent
   def group_bar_width
-    [@ordergroup.apples, 2].max
+    @ordergroup.apples < 2 ? 2 : @ordergroup.apples
   end
 
   def mean_order_amount_per_job
diff --git a/lib/tasks/db_shared.rake b/lib/tasks/db_shared.rake
index f2fd7046..eb0230b4 100644
--- a/lib/tasks/db_shared.rake
+++ b/lib/tasks/db_shared.rake
@@ -3,21 +3,21 @@ task spec: ['shared:db:test:prepare']
 namespace :shared do
   namespace :db do |ns|
     [:drop, :create, :setup, :migrate, :rollback, :seed, :version].each do |task_name|
-      task task_name => :environment do
+      task task_name do
         Rake::Task["db:#{task_name}"].invoke
       end
     end
 
     namespace :schema do
       [:load, :dump].each do |task_name|
-        task task_name => :environment do
+        task task_name do
           Rake::Task["db:schema:#{task_name}"].invoke
         end
       end
     end
 
     namespace :test do
-      task prepare: :environment do
+      task :prepare do
         Rake::Task['db:test:prepare'].invoke
       end
     end
@@ -33,7 +33,7 @@ namespace :shared do
   task set_custom_config: :environment do
     # save current vars
     @original_config = {
-      env_schema: ENV.fetch('SCHEMA', nil),
+      env_schema: ENV['SCHEMA'],
       config: Rails.application.config.dup
     }
 
diff --git a/lib/tasks/foodsoft.rake b/lib/tasks/foodsoft.rake
index 760cd5bc..5a5c6fa0 100644
--- a/lib/tasks/foodsoft.rake
+++ b/lib/tasks/foodsoft.rake
@@ -51,13 +51,13 @@ namespace :foodsoft do
 
   desc "Parse incoming email on stdin (options: RECIPIENT=foodcoop.handling)"
   task :parse_reply_email => :environment do
-    FoodsoftMailReceiver.received ENV.fetch('RECIPIENT', nil), STDIN.read
+    FoodsoftMailReceiver.received ENV['RECIPIENT'], STDIN.read
   end
 
   desc "Start STMP server for incoming email (options: SMTP_SERVER_PORT=2525, SMTP_SERVER_HOST=0.0.0.0)"
   task :reply_email_smtp_server => :environment do
     port = ENV['SMTP_SERVER_PORT'].present? ? ENV['SMTP_SERVER_PORT'].to_i : 2525
-    host = ENV.fetch('SMTP_SERVER_HOST', nil)
+    host = ENV['SMTP_SERVER_HOST']
     rake_say "Started SMTP server for incoming email on port #{port}."
     server = FoodsoftMailReceiver.new(ports: port, hosts: host, max_processings: 1, logger: Rails.logger)
     server.start
diff --git a/lib/tasks/multicoops.rake b/lib/tasks/multicoops.rake
index f0c76b8f..cb2f280a 100644
--- a/lib/tasks/multicoops.rake
+++ b/lib/tasks/multicoops.rake
@@ -5,7 +5,7 @@
 namespace :multicoops do
   desc 'Runs a specific rake task for each registered foodcoop, use rake multicoops:run TASK=db:migrate'
   task :run => :environment do
-    task_to_run = ENV.fetch('TASK', nil)
+    task_to_run = ENV['TASK']
     last_error = nil
     FoodsoftConfig.each_coop do |coop|
       begin
@@ -21,9 +21,9 @@ namespace :multicoops do
 
   desc 'Runs a specific rake task for a single coop, use rake mutlicoops:run_single TASK=db:migrate FOODCOOP=demo'
   task :run_single => :environment do
-    task_to_run = ENV.fetch('TASK', nil)
-    FoodsoftConfig.select_foodcoop ENV.fetch('FOODCOOP', nil)
-    rake_say "Run '#{task_to_run}' for #{ENV.fetch('FOODCOOP', nil)}"
+    task_to_run = ENV['TASK']
+    FoodsoftConfig.select_foodcoop ENV['FOODCOOP']
+    rake_say "Run '#{task_to_run}' for #{ENV['FOODCOOP']}"
     Rake::Task[task_to_run].execute
   end
 end
diff --git a/lib/tasks/seeds.rake b/lib/tasks/seeds.rake
index 2437befe..36e0c201 100644
--- a/lib/tasks/seeds.rake
+++ b/lib/tasks/seeds.rake
@@ -6,7 +6,7 @@ require 'pathname'
 
 namespace :db do
   namespace :seed do
-    Dir.glob(Rails.root.join('db/seeds/*.seeds.rb')).sort.each do |seedfile|
+    Dir.glob(Rails.root.join('db/seeds/*.seeds.rb')).each do |seedfile|
       desc "Load the seed data from #{Pathname.new(seedfile).relative_path_from(Rails.root)}"
       task File.basename(seedfile, '.seeds.rb') => :environment do
         require_relative seedfile
diff --git a/plugins/discourse/foodsoft_discourse.gemspec b/plugins/discourse/foodsoft_discourse.gemspec
index 4400bcf4..6d2fb5d4 100644
--- a/plugins/discourse/foodsoft_discourse.gemspec
+++ b/plugins/discourse/foodsoft_discourse.gemspec
@@ -14,6 +14,7 @@ Gem::Specification.new do |s|
   s.description = "Allow SSO login via Discourse"
 
   s.files = Dir["{app,config,db,lib}/**/*"] + ["Rakefile", "README.md"]
+  s.test_files = Dir["test/**/*"]
 
   s.add_dependency "rails"
   s.add_dependency "deface", "~> 1.0"
diff --git a/plugins/documents/foodsoft_documents.gemspec b/plugins/documents/foodsoft_documents.gemspec
index 1301fa11..c0a4f8fd 100644
--- a/plugins/documents/foodsoft_documents.gemspec
+++ b/plugins/documents/foodsoft_documents.gemspec
@@ -14,6 +14,7 @@ Gem::Specification.new do |s|
   s.description = "Adds simple document management to foodsoft."
 
   s.files = Dir["{app,config,db,lib}/**/*"] + ["Rakefile", "README.md"]
+  s.test_files = Dir["test/**/*"]
 
   s.add_dependency "rails"
   s.add_dependency "deface", "~> 1.0"
diff --git a/plugins/links/foodsoft_links.gemspec b/plugins/links/foodsoft_links.gemspec
index e899c082..04fc03f9 100644
--- a/plugins/links/foodsoft_links.gemspec
+++ b/plugins/links/foodsoft_links.gemspec
@@ -14,6 +14,7 @@ Gem::Specification.new do |s|
   s.description = "Adds simple link management to foodsoft."
 
   s.files = Dir["{app,config,db,lib}/**/*"] + ["Rakefile", "README.md"]
+  s.test_files = Dir["test/**/*"]
 
   s.add_dependency "rails"
   s.add_dependency "deface", "~> 1.0"
diff --git a/plugins/messages/foodsoft_messages.gemspec b/plugins/messages/foodsoft_messages.gemspec
index 0dfc7163..13050bf8 100644
--- a/plugins/messages/foodsoft_messages.gemspec
+++ b/plugins/messages/foodsoft_messages.gemspec
@@ -14,6 +14,7 @@ Gem::Specification.new do |s|
   s.description = "Adds the ability to exchange messages to foodsoft."
 
   s.files = Dir["{app,config,db,lib}/**/*"] + ["Rakefile", "README.md"]
+  s.test_files = Dir["test/**/*"]
 
   s.add_dependency "rails"
   s.add_dependency "base32"
diff --git a/plugins/polls/foodsoft_polls.gemspec b/plugins/polls/foodsoft_polls.gemspec
index 63e7db29..e5b25173 100644
--- a/plugins/polls/foodsoft_polls.gemspec
+++ b/plugins/polls/foodsoft_polls.gemspec
@@ -14,6 +14,7 @@ Gem::Specification.new do |s|
   s.description = "Adds possibility to do polls with foodsoft."
 
   s.files = Dir["{app,config,db,lib}/**/*"] + ["Rakefile", "README.md"]
+  s.test_files = Dir["test/**/*"]
 
   s.add_dependency "rails"
   s.add_dependency "deface", "~> 1.0"
diff --git a/plugins/printer/foodsoft_printer.gemspec b/plugins/printer/foodsoft_printer.gemspec
index d0eea89a..cf249593 100644
--- a/plugins/printer/foodsoft_printer.gemspec
+++ b/plugins/printer/foodsoft_printer.gemspec
@@ -14,6 +14,7 @@ Gem::Specification.new do |s|
   s.description = "Add a printer queue to foodsoft."
 
   s.files = Dir["{app,config,db,lib}/**/*"] + ["Rakefile", "README.md"]
+  s.test_files = Dir["test/**/*"]
 
   s.add_dependency "rails"
   s.add_dependency "deface", "~> 1.0"
diff --git a/plugins/wiki/foodsoft_wiki.gemspec b/plugins/wiki/foodsoft_wiki.gemspec
index 371872c5..07f0c182 100644
--- a/plugins/wiki/foodsoft_wiki.gemspec
+++ b/plugins/wiki/foodsoft_wiki.gemspec
@@ -14,6 +14,7 @@ Gem::Specification.new do |s|
   s.description = "Adds a wiki to foodsoft."
 
   s.files = Dir["{app,config,db,lib}/**/*"] + ["Rakefile", "README.md"]
+  s.test_files = Dir["test/**/*"]
 
   s.add_dependency "rails"
   s.add_dependency 'wikicloth'
diff --git a/spec/lib/bank_account_information_importer_spec.rb b/spec/lib/bank_account_information_importer_spec.rb
index a5d32485..a98441d2 100644
--- a/spec/lib/bank_account_information_importer_spec.rb
+++ b/spec/lib/bank_account_information_importer_spec.rb
@@ -4,7 +4,8 @@
   let(:bank_account) { create :bank_account }
 
   it 'empty content' do
-    content = ''
+    content = <<-JSON
+    JSON
 
     importer = BankAccountInformationImporter.new(bank_account)
     expect(importer.import!(content)).to be(nil)