diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 46e75337..56b8016f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,26 +8,11 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ['2.6', '2.7', '3.0', '3.1', '3.2']
+        ruby: ['3.0', '3.1', '3.2']
         gemfile:
-          - gemfiles/rails_5_2.gemfile
-          - gemfiles/rails_6_0.gemfile
           - gemfiles/rails_6_1.gemfile
           - gemfiles/rails_7_0.gemfile
           - gemfiles/rails_7_1.gemfile
-        exclude:
-          - ruby: '3.2'
-            gemfile: gemfiles/rails_5_2.gemfile
-          - ruby: '3.1'
-            gemfile: gemfiles/rails_5_2.gemfile
-          - ruby: '3.0'
-            gemfile: gemfiles/rails_5_2.gemfile
-          - ruby: '2.7'
-            gemfile: gemfiles/rails_7_1.gemfile
-          - ruby: '2.6'
-            gemfile: gemfiles/rails_7_1.gemfile
-          - ruby: '2.6'
-            gemfile: gemfiles/rails_7_0.gemfile
     services:
       postgres:
         image: postgres
diff --git a/.github/workflows/linter.yml b/.github/workflows/linter.yml
index 857bb4d4..70cd6c71 100644
--- a/.github/workflows/linter.yml
+++ b/.github/workflows/linter.yml
@@ -8,10 +8,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Ruby 2.7
+    - name: Set up Ruby 3.0
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 2.7
+        ruby-version: 3.0
         bundler-cache: true
     - name: Run Linter
       run: bundle exec rubocop --parallel
diff --git a/.rubocop.yml b/.rubocop.yml
index 637eed70..a98714a0 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -9,10 +9,13 @@ inherit_mode:
     - Exclude
 
 AllCops:
-  TargetRubyVersion: 2.6
+  TargetRubyVersion: 3.0
   Exclude:
     - 'lib/generators/delayed/templates/*.rb'
   NewCops: enable
 
 Rails/EnvironmentVariableAccess:
   Enabled: false
+
+Style/FrozenStringLiteralComment:
+  Enabled: false
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 73641032..34acfc47 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config --auto-gen-only-exclude --exclude-limit 99999`
-# on 2023-01-20 19:16:15 UTC using RuboCop version 1.43.0.
+# on 2023-12-28 21:29:05 UTC using RuboCop version 1.59.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -33,6 +33,7 @@ Lint/ConstantDefinitionInBlock:
     - 'spec/message_sending_spec.rb'
 
 # Offense count: 2
+# Configuration parameters: AllowedParentClasses.
 Lint/MissingSuper:
   Exclude:
     - 'lib/delayed/message_sending.rb'
@@ -50,7 +51,7 @@ Lint/SuppressedException:
     - 'lib/delayed/backend/base.rb'
 
 # Offense count: 4
-# Configuration parameters: AllowedMethods, AllowedPatterns, IgnoredMethods, CountRepeatedAttributes, Max.
+# Configuration parameters: AllowedMethods, AllowedPatterns, CountRepeatedAttributes, Max.
 Metrics/AbcSize:
   Exclude:
     - 'lib/delayed/message_sending.rb'
@@ -62,14 +63,6 @@ RSpec/AnyInstance:
   Exclude:
     - 'spec/delayed/job_spec.rb'
 
-# Offense count: 18
-# This cop supports unsafe autocorrection (--autocorrect-all).
-RSpec/BeEq:
-  Exclude:
-    - 'spec/delayed/job_spec.rb'
-    - 'spec/delayed/priority_spec.rb'
-    - 'spec/message_sending_spec.rb'
-
 # Offense count: 1
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle.
@@ -165,11 +158,10 @@ Rake/DuplicateTask:
   Exclude:
     - 'Rakefile'
 
-# Offense count: 4
+# Offense count: 2
 # This cop supports unsafe autocorrection (--autocorrect-all).
 Security/YAMLLoad:
   Exclude:
-    - 'spec/delayed/serialization/active_record_spec.rb'
     - 'spec/helper.rb'
     - 'spec/yaml_ext_spec.rb'
 
diff --git a/.ruby-version b/.ruby-version
index a603bb50..be94e6f5 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.7.5
+3.2.2
diff --git a/Appraisals b/Appraisals
index 8e8f0c3a..8b212694 100644
--- a/Appraisals
+++ b/Appraisals
@@ -1,15 +1,3 @@
-appraise 'rails-5-2' do
-  gem 'actionmailer', '~> 5.2.0'
-  gem 'activejob', '~> 5.2.0'
-  gem 'activerecord', '~> 5.2.0'
-end
-
-appraise 'rails-6-0' do
-  gem 'actionmailer', '~> 6.0.0'
-  gem 'activejob', '~> 6.0.0'
-  gem 'activerecord', '~> 6.0.0'
-end
-
 appraise 'rails-6-1' do
   gem 'actionmailer', '~> 6.1.0'
   gem 'activejob', '~> 6.1.0'
diff --git a/delayed.gemspec b/delayed.gemspec
index 0e4b0b9c..7412835c 100644
--- a/delayed.gemspec
+++ b/delayed.gemspec
@@ -18,15 +18,15 @@ Gem::Specification.new do |spec|
   spec.require_paths  = ['lib']
   spec.summary        = 'a multi-threaded, SQL-driven ActiveJob backend used at Betterment to process millions of background jobs per day'
 
-  spec.version        = '0.5.2'
+  spec.version        = '0.6.0'
   spec.metadata       = {
     'changelog_uri' => 'https://github.com/betterment/delayed/blob/main/CHANGELOG.md',
     'bug_tracker_uri' => 'https://github.com/betterment/delayed/issues',
     'source_code_uri' => 'https://github.com/betterment/delayed',
     'rubygems_mfa_required' => 'true',
   }
-  spec.required_ruby_version = '>= 2.6'
+  spec.required_ruby_version = '>= 3.0'
 
-  spec.add_dependency 'activerecord', '>= 5.2'
+  spec.add_dependency 'activerecord', '>= 6.1'
   spec.add_dependency 'concurrent-ruby'
 end
diff --git a/gemfiles/rails_5_2.gemfile b/gemfiles/rails_5_2.gemfile
deleted file mode 100644
index da3da842..00000000
--- a/gemfiles/rails_5_2.gemfile
+++ /dev/null
@@ -1,18 +0,0 @@
-# This file was generated by Appraisal
-
-source "https://rubygems.org"
-
-gem "actionmailer", "~> 5.2.0"
-gem "activejob", "~> 5.2.0"
-gem "activerecord", "~> 5.2.0"
-gem "appraisal"
-gem "betterlint"
-gem "mysql2"
-gem "pg"
-gem "rake"
-gem "rspec"
-gem "sqlite3"
-gem "timecop"
-gem "zeitwerk"
-
-gemspec path: "../"
diff --git a/gemfiles/rails_6_0.gemfile b/gemfiles/rails_6_0.gemfile
deleted file mode 100644
index bff971b3..00000000
--- a/gemfiles/rails_6_0.gemfile
+++ /dev/null
@@ -1,18 +0,0 @@
-# This file was generated by Appraisal
-
-source "https://rubygems.org"
-
-gem "actionmailer", "~> 6.0.0"
-gem "activejob", "~> 6.0.0"
-gem "activerecord", "~> 6.0.0"
-gem "appraisal"
-gem "betterlint"
-gem "mysql2"
-gem "pg"
-gem "rake"
-gem "rspec"
-gem "sqlite3"
-gem "timecop"
-gem "zeitwerk"
-
-gemspec path: "../"
diff --git a/lib/delayed.rb b/lib/delayed.rb
index 2fb97829..eacc7363 100644
--- a/lib/delayed.rb
+++ b/lib/delayed.rb
@@ -39,7 +39,7 @@
 module Delayed
   autoload :PerformableMailer, 'delayed/performable_mailer'
 
-  mattr_accessor(:default_log_level) { 'info'.freeze }
+  mattr_accessor(:default_log_level) { 'info' }
   mattr_accessor(:plugins) do
     [
       Delayed::Plugins::Instrumentation,
diff --git a/lib/delayed/backend/base.rb b/lib/delayed/backend/base.rb
index 62369bf2..75e3c3c6 100644
--- a/lib/delayed/backend/base.rb
+++ b/lib/delayed/backend/base.rb
@@ -55,7 +55,7 @@ def failed?
       end
       alias failed failed?
 
-      ParseObjectFromYaml = %r{!ruby/\w+:([^\s]+)}.freeze # rubocop:disable Naming/ConstantName
+      ParseObjectFromYaml = %r{!ruby/\w+:([^\s]+)} # rubocop:disable Naming/ConstantName
 
       def name # rubocop:disable Metrics/AbcSize
         @name ||= payload_object.job_data['job_class'] if payload_object.respond_to?(:job_data)
diff --git a/lib/delayed/monitor.rb b/lib/delayed/monitor.rb
index d2979693..98c13446 100644
--- a/lib/delayed/monitor.rb
+++ b/lib/delayed/monitor.rb
@@ -34,7 +34,7 @@ def run!
     attr_reader :jobs
 
     def emit_metric!(metric)
-      send("#{metric}_grouped").reverse_merge(default_results).each do |(priority, queue), value|
+      send(:"#{metric}_grouped").reverse_merge(default_results).each do |(priority, queue), value|
         ActiveSupport::Notifications.instrument(
           "delayed.job.#{metric}",
           default_tags.merge(priority: Priority.new(priority).to_s, queue: queue, value: value),
diff --git a/lib/delayed/performable_method.rb b/lib/delayed/performable_method.rb
index 8b6d46d9..2afb47e2 100644
--- a/lib/delayed/performable_method.rb
+++ b/lib/delayed/performable_method.rb
@@ -26,7 +26,7 @@ def display_name
     def perform
       return unless object
 
-      if kwargs.nil? || (RUBY_VERSION < '2.7' && kwargs.empty?)
+      if kwargs.nil?
         object.send(method_name, *args)
       else
         object.send(method_name, *args, **kwargs)