diff --git a/Gemfile b/Gemfile
index 0e4d83d..f6c1340 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source "https://rubygems.org"
 
-gem "rails", "~> 5.2"
+gem "rails", "~> 6.1.7"
 gem "dotenv"
 gem "oj", ">= 3.1.0"
 gem "oj_mimic_json", "~> 1.0", ">= 1.0.1"
@@ -22,22 +22,19 @@ gem "rack-cors", "~> 1.0", require: "rack/cors"
 gem "git", "~> 1.5"
 gem "sprockets", "~> 3.7", ">= 3.7.2"
 
-group :development do
+group :development, :test do
   gem "better_errors"
   gem "binding_of_caller"
   gem "listen", "~> 3.0.5"
-  gem "rubocop", "~> 0.77.0"
+  gem "rubocop", "~> 1.3", ">= 1.3.1"
   gem "rubocop-performance", "~> 1.5", ">= 1.5.1"
-  gem "rubocop-rails", "~> 2.4"
+  gem "rubocop-rails", "~> 2.8", ">= 2.8.1"
   gem "spring"
   gem "spring-watcher-listen", "~> 2.0.0"
   gem 'byebug'
-end
-
-group :test do
-  gem "rspec-rails", "~> 3.5", ">= 3.5.2"
+  gem "rspec-rails", "~> 3.8", ">= 3.8.2"
   gem "capybara"
   gem "webmock", "~> 3.8", ">= 3.8.2"
-  gem "vcr", "~> 3.0.3"
+  gem "vcr", "~> 5.1"
   gem 'simplecov', '~> 0.17.1'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index c440050..d671925 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,50 +1,67 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    actioncable (5.2.6)
-      actionpack (= 5.2.6)
+    actioncable (6.1.7.6)
+      actionpack (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
-    actionmailer (5.2.6)
-      actionpack (= 5.2.6)
-      actionview (= 5.2.6)
-      activejob (= 5.2.6)
+    actionmailbox (6.1.7.6)
+      actionpack (= 6.1.7.6)
+      activejob (= 6.1.7.6)
+      activerecord (= 6.1.7.6)
+      activestorage (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
+      mail (>= 2.7.1)
+    actionmailer (6.1.7.6)
+      actionpack (= 6.1.7.6)
+      actionview (= 6.1.7.6)
+      activejob (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 2.0)
-    actionpack (5.2.6)
-      actionview (= 5.2.6)
-      activesupport (= 5.2.6)
-      rack (~> 2.0, >= 2.0.8)
+    actionpack (6.1.7.6)
+      actionview (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
+      rack (~> 2.0, >= 2.0.9)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
-      rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.2.6)
-      activesupport (= 5.2.6)
+      rails-html-sanitizer (~> 1.0, >= 1.2.0)
+    actiontext (6.1.7.6)
+      actionpack (= 6.1.7.6)
+      activerecord (= 6.1.7.6)
+      activestorage (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
+      nokogiri (>= 1.8.5)
+    actionview (6.1.7.6)
+      activesupport (= 6.1.7.6)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
-      rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (5.2.6)
-      activesupport (= 5.2.6)
+      rails-html-sanitizer (~> 1.1, >= 1.2.0)
+    activejob (6.1.7.6)
+      activesupport (= 6.1.7.6)
       globalid (>= 0.3.6)
-    activemodel (5.2.6)
-      activesupport (= 5.2.6)
-    activerecord (5.2.6)
-      activemodel (= 5.2.6)
-      activesupport (= 5.2.6)
-      arel (>= 9.0)
-    activestorage (5.2.6)
-      actionpack (= 5.2.6)
-      activerecord (= 5.2.6)
-      marcel (~> 1.0.0)
-    activesupport (5.2.6)
+    activemodel (6.1.7.6)
+      activesupport (= 6.1.7.6)
+    activerecord (6.1.7.6)
+      activemodel (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
+    activestorage (6.1.7.6)
+      actionpack (= 6.1.7.6)
+      activejob (= 6.1.7.6)
+      activerecord (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
+      marcel (~> 1.0)
+      mini_mime (>= 1.1.0)
+    activesupport (6.1.7.6)
       concurrent-ruby (~> 1.0, >= 1.0.2)
-      i18n (>= 0.7, < 2)
-      minitest (~> 5.1)
-      tzinfo (~> 1.1)
+      i18n (>= 1.6, < 2)
+      minitest (>= 5.1)
+      tzinfo (~> 2.0)
+      zeitwerk (~> 2.3)
     addressable (2.8.1)
       public_suffix (>= 2.0.2, < 6.0)
-    arel (9.0.0)
     ast (2.4.2)
     benchmark_methods (0.7)
     better_errors (2.9.1)
@@ -107,6 +124,7 @@ GEM
     csl-styles (1.0.1.11)
       csl (~> 1.0)
     dalli (2.7.11)
+    date (3.3.4)
     debug_inspector (1.1.0)
     diff-lcs (1.5.0)
     docile (1.4.0)
@@ -134,14 +152,13 @@ GEM
       unicode_utils (>= 1.3.0)
     git (1.10.1)
       rchardet (~> 1.8)
-    globalid (1.0.0)
-      activesupport (>= 5.0)
+    globalid (1.2.1)
+      activesupport (>= 6.1)
     hashdiff (1.0.1)
     htmlentities (4.3.4)
     i18n (1.14.1)
       concurrent-ruby (~> 1.0)
     iso8601 (0.9.1)
-    jaro_winkler (1.5.4)
     json (2.6.1)
     json-canonicalization (0.3.1)
     json-ld (3.2.4)
@@ -173,8 +190,11 @@ GEM
     loofah (2.21.3)
       crass (~> 1.0.2)
       nokogiri (>= 1.12.0)
-    mail (2.7.1)
+    mail (2.8.1)
       mini_mime (>= 0.1.1)
+      net-imap
+      net-pop
+      net-smtp
     marcel (1.0.2)
     maremma (4.9.8)
       activesupport (>= 4.2.5)
@@ -194,15 +214,25 @@ GEM
     multi_json (1.15.0)
     multipart-post (2.3.0)
     namae (1.1.1)
-    nio4r (2.5.8)
+    net-imap (0.3.7)
+      date
+      net-protocol
+    net-pop (0.1.2)
+      net-protocol
+    net-protocol (0.2.2)
+      timeout
+    net-smtp (0.4.0)
+      net-protocol
+    nio4r (2.7.0)
     nokogiri (1.13.10-x86_64-darwin)
       racc (~> 1.4)
     oj (3.14.2)
     oj_mimic_json (1.0.1)
     optimist (3.1.0)
-    parallel (1.21.0)
-    parser (3.1.0.0)
+    parallel (1.23.0)
+    parser (3.2.2.4)
       ast (~> 2.4.1)
+      racc
     postrank-uri (1.1)
       addressable (>= 2.4.0)
       nokogiri (>= 1.8.0)
@@ -214,31 +244,33 @@ GEM
       rack (>= 2.0.0)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rails (5.2.6)
-      actioncable (= 5.2.6)
-      actionmailer (= 5.2.6)
-      actionpack (= 5.2.6)
-      actionview (= 5.2.6)
-      activejob (= 5.2.6)
-      activemodel (= 5.2.6)
-      activerecord (= 5.2.6)
-      activestorage (= 5.2.6)
-      activesupport (= 5.2.6)
-      bundler (>= 1.3.0)
-      railties (= 5.2.6)
+    rails (6.1.7.6)
+      actioncable (= 6.1.7.6)
+      actionmailbox (= 6.1.7.6)
+      actionmailer (= 6.1.7.6)
+      actionpack (= 6.1.7.6)
+      actiontext (= 6.1.7.6)
+      actionview (= 6.1.7.6)
+      activejob (= 6.1.7.6)
+      activemodel (= 6.1.7.6)
+      activerecord (= 6.1.7.6)
+      activestorage (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
+      bundler (>= 1.15.0)
+      railties (= 6.1.7.6)
       sprockets-rails (>= 2.0.0)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
     rails-html-sanitizer (1.4.2)
       loofah (~> 2.3)
-    railties (5.2.6)
-      actionpack (= 5.2.6)
-      activesupport (= 5.2.6)
+    railties (6.1.7.6)
+      actionpack (= 6.1.7.6)
+      activesupport (= 6.1.7.6)
       method_source
-      rake (>= 0.8.7)
-      thor (>= 0.19.0, < 2.0)
-    rainbow (3.0.0)
+      rake (>= 12.2)
+      thor (~> 1.0)
+    rainbow (3.1.1)
     rake (13.0.6)
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
@@ -278,20 +310,25 @@ GEM
       rspec-mocks (~> 3.9.0)
       rspec-support (~> 3.9.0)
     rspec-support (3.9.4)
-    rubocop (0.77.0)
-      jaro_winkler (~> 1.5.1)
+    rubocop (1.50.2)
+      json (~> 2.3)
       parallel (~> 1.10)
-      parser (>= 2.6)
+      parser (>= 3.2.0.0)
       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)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 1.7)
+      unicode-display_width (>= 2.4.0, < 3.0)
+    rubocop-ast (1.30.0)
+      parser (>= 3.2.1.0)
     rubocop-performance (1.6.1)
       rubocop (>= 0.71.0)
-    rubocop-rails (2.5.2)
-      activesupport
+    rubocop-rails (2.19.1)
+      activesupport (>= 4.2.0)
       rack (>= 1.1)
-      rubocop (>= 0.72.0)
-    ruby-progressbar (1.11.0)
+      rubocop (>= 1.33.0, < 2.0)
+    ruby-progressbar (1.13.0)
     scanf (1.0.0)
     sentry-raven (2.13.0)
       faraday (>= 0.7.6, < 1.0)
@@ -315,22 +352,23 @@ GEM
       matrix (~> 0.4)
       rdf (~> 3.2)
     thor (1.2.2)
-    thread_safe (0.3.6)
-    tzinfo (1.2.11)
-      thread_safe (~> 0.1)
-    unicode-display_width (1.6.1)
+    timeout (0.4.1)
+    tzinfo (2.0.6)
+      concurrent-ruby (~> 1.0)
+    unicode-display_width (2.5.0)
     unicode-types (1.9.0)
     unicode_utils (1.4.0)
-    vcr (3.0.3)
+    vcr (5.1.0)
     webmock (3.14.0)
       addressable (>= 2.8.0)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)
-    websocket-driver (0.7.5)
+    websocket-driver (0.7.6)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
     xpath (3.2.0)
       nokogiri (~> 1.8)
+    zeitwerk (2.6.12)
 
 PLATFORMS
   x86_64-darwin-20
@@ -359,17 +397,17 @@ DEPENDENCIES
   oj (>= 3.1.0)
   oj_mimic_json (~> 1.0, >= 1.0.1)
   rack-cors (~> 1.0)
-  rails (~> 5.2)
-  rspec-rails (~> 3.5, >= 3.5.2)
-  rubocop (~> 0.77.0)
+  rails (~> 6.1.7)
+  rspec-rails (~> 3.8, >= 3.8.2)
+  rubocop (~> 1.3, >= 1.3.1)
   rubocop-performance (~> 1.5, >= 1.5.1)
-  rubocop-rails (~> 2.4)
+  rubocop-rails (~> 2.8, >= 2.8.1)
   sentry-raven (~> 2.9)
   simplecov (~> 0.17.1)
   spring
   spring-watcher-listen (~> 2.0.0)
   sprockets (~> 3.7, >= 3.7.2)
-  vcr (~> 3.0.3)
+  vcr (~> 5.1)
   webmock (~> 3.8, >= 3.8.2)
 
 BUNDLED WITH
diff --git a/config/application.rb b/config/application.rb
index 92e4522..a3c8a00 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -38,6 +38,7 @@
 
 module ContentNegotiation
   class Application < Rails::Application
+    config.load_defaults 6.1
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration should go into files in config/initializers
     # -- all .rb files in that directory are automatically loaded.
diff --git a/config/routes.rb b/config/routes.rb
index d94f342..3e9cb5e 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -17,7 +17,7 @@
   get '/application/x-turtle/:id', :to => 'index#show', constraints: { :id => /.+/ }, defaults: { format: :turtle }
   get '/text/x-bibliography/:id', :to => 'index#show', constraints: { :id => /.+/ }, defaults: { format: :citation }
   
-  resources :index, path: '/', only: [:show, :index], constraints: { id: /.+/, format: false }
+  resources :index, path: '/', only: [:show, :index], constraints: { id: /.+/ }
   root :to => 'index#index'
 
   # rescue method not allowed errors
diff --git a/spec/routing/index_routing_spec.rb b/spec/routing/index_routing_spec.rb
new file mode 100644
index 0000000..0483005
--- /dev/null
+++ b/spec/routing/index_routing_spec.rb
@@ -0,0 +1,35 @@
+require 'rails_helper'
+
+RSpec.describe 'Index routing', type: :routing do
+  it 'routes GET / to index#index' do
+    expect(get: '/').to route_to(controller: 'index', action: 'index')
+  end
+
+  it 'routes GET /index to index#show' do
+    expect(get: '/index').to route_to(controller: 'index', action: 'show', id: 'index')
+  end
+
+  it 'does not route GET /index.xml to index#show' do
+    expect(get: '/index.xml').not_to route_to(controller: 'index', action: 'show', id: 'index', format: 'xml')
+  end
+
+  it 'routes GET /custom_id to index#show with custom_id' do
+    expect(get: '/custom_id').to route_to(controller: 'index', action: 'show', id: 'custom_id')
+  end
+
+  it 'does not route GET /custom_id.xml to index#show with custom_id and xml format' do
+    expect(get: '/custom_id.xml').not_to route_to(controller: 'index', action: 'show', id: 'custom_id', format: 'xml')
+  end
+
+  it 'routes GET / with format: false to index#index' do
+    expect(get: '/', constraints: { format: false }).to route_to(controller: 'index', action: 'index')
+  end
+
+  it 'does not route GET /index.xml with format: false to index#show' do
+    expect(get: '/index.xml', constraints: { format: false }).not_to route_to(controller: 'index', action: 'show', id: 'index', format: 'xml')
+  end
+
+  it 'does not route GET /custom_id.xml with format: false to index#show with custom_id' do
+    expect(get: '/custom_id.xml', constraints: { format: false }).not_to route_to(controller: 'index', action: 'show', id: 'custom_id', format: 'xml')
+  end
+end