diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 8f33baa36..f1e330d1f 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -13,8 +13,8 @@ jobs:
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
-          bundler: 2.3.4
+          ruby-version: 3.1
+          bundler: 2.3.6
           bundler-cache: true
       - run: bin/bundle --jobs=$(nproc) --retry=$(nproc)
       - run: bin/rubocop -P
@@ -28,8 +28,8 @@ jobs:
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
-          bundler: 2.3.4
+          ruby-version: 3.1
+          bundler: 2.3.6
           bundler-cache: true
       - run: bin/bundle --jobs=$(nproc) --retry=$(nproc)
       - run: bin/reek .
diff --git a/.github/workflows/rspec.yml b/.github/workflows/rspec.yml
index e14e4bf7b..bf0111e82 100644
--- a/.github/workflows/rspec.yml
+++ b/.github/workflows/rspec.yml
@@ -17,8 +17,8 @@ jobs:
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
-          bundler: 2.3.4
+          ruby-version: 3.1
+          bundler: 2.3.6
           bundler-cache: true
 
       - name: Install Code Climate reporter
diff --git a/.reek.yml b/.reek.yml
index 36f40b6ee..29d3e7821 100644
--- a/.reek.yml
+++ b/.reek.yml
@@ -7,7 +7,7 @@ exclude_paths:
   - myapp
   - spec
   - tmp
-  - vendor/bundle
+  - vendor
 detectors:
   BooleanParameter:
     exclude:
@@ -102,6 +102,7 @@ detectors:
       - SidekiqUniqueJobs::Changelog#entries
       - SidekiqUniqueJobs::Changelog#page
       - SidekiqUniqueJobs::Digests#page
+      - SidekiqUniqueJobs::Lock#lock
       - SidekiqUniqueJobs::Locksmith#create_lock
       - SidekiqUniqueJobs::Locksmith#lock!
       - SidekiqUniqueJobs::Middleware#self.configure_client
diff --git a/Appraisals b/Appraisals
index fa71bba83..d792f698d 100644
--- a/Appraisals
+++ b/Appraisals
@@ -27,3 +27,11 @@ end
 appraise "sidekiq-6.2" do
   gem "sidekiq", "~> 6.2.2"
 end
+
+appraise "sidekiq-6.3" do
+  gem "sidekiq", "~> 6.3.0"
+end
+
+appraise "sidekiq-6.4" do
+  gem "sidekiq", "~> 6.4.0"
+end
diff --git a/gemfiles/sidekiq_6.3.gemfile b/gemfiles/sidekiq_6.3.gemfile
new file mode 100644
index 000000000..39f9effaf
--- /dev/null
+++ b/gemfiles/sidekiq_6.3.gemfile
@@ -0,0 +1,27 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "appraisal"
+gem "gem-release"
+gem "github-markup"
+gem "rack-test"
+gem "rake", "13.0.3"
+gem "reek", ">= 5.3"
+gem "rspec"
+gem "rspec-benchmark"
+gem "rspec-html-matchers"
+gem "rspec-its"
+gem "rubocop-mhenrixon"
+gem "simplecov-sublime", ">= 0.21.2", require: false
+gem "sinatra"
+gem "timecop"
+gem "yard"
+gem "sidekiq", "~> 6.3.0"
+
+platforms :mri do
+  gem "concurrent-ruby-ext"
+  gem "hiredis"
+end
+
+gemspec path: "../"
diff --git a/gemfiles/sidekiq_6.4.gemfile b/gemfiles/sidekiq_6.4.gemfile
new file mode 100644
index 000000000..33c10d37f
--- /dev/null
+++ b/gemfiles/sidekiq_6.4.gemfile
@@ -0,0 +1,27 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "appraisal"
+gem "gem-release"
+gem "github-markup"
+gem "rack-test"
+gem "rake", "13.0.3"
+gem "reek", ">= 5.3"
+gem "rspec"
+gem "rspec-benchmark"
+gem "rspec-html-matchers"
+gem "rspec-its"
+gem "rubocop-mhenrixon"
+gem "simplecov-sublime", ">= 0.21.2", require: false
+gem "sinatra"
+gem "timecop"
+gem "yard"
+gem "sidekiq", "~> 6.4.0"
+
+platforms :mri do
+  gem "concurrent-ruby-ext"
+  gem "hiredis"
+end
+
+gemspec path: "../"
diff --git a/lib/sidekiq_unique_jobs/changelog.rb b/lib/sidekiq_unique_jobs/changelog.rb
index 4d938b049..b802bfaad 100644
--- a/lib/sidekiq_unique_jobs/changelog.rb
+++ b/lib/sidekiq_unique_jobs/changelog.rb
@@ -62,9 +62,9 @@ def entries(pattern: SCAN_PATTERN, count: DEFAULT_COUNT)
     #
     def page(cursor: 0, pattern: "*", page_size: 100)
       redis do |conn|
-        total_size, result = conn.multi do
-          conn.zcard(key)
-          conn.zscan(key, cursor, match: pattern, count: page_size)
+        total_size, result = conn.multi do |pipeline|
+          pipeline.zcard(key)
+          pipeline.zscan(key, cursor, match: pattern, count: page_size)
         end
 
         [
diff --git a/lib/sidekiq_unique_jobs/digests.rb b/lib/sidekiq_unique_jobs/digests.rb
index e70ab92f9..c6552116f 100644
--- a/lib/sidekiq_unique_jobs/digests.rb
+++ b/lib/sidekiq_unique_jobs/digests.rb
@@ -95,9 +95,9 @@ def entries(pattern: SCAN_PATTERN, count: DEFAULT_COUNT)
     #
     def page(cursor: 0, pattern: SCAN_PATTERN, page_size: 100)
       redis do |conn|
-        total_size, digests = conn.multi do
-          conn.zcard(key)
-          conn.zscan(key, cursor, match: pattern, count: page_size)
+        total_size, digests = conn.multi do |pipeline|
+          pipeline.zcard(key)
+          pipeline.zscan(key, cursor, match: pattern, count: page_size)
         end
 
         [
diff --git a/lib/sidekiq_unique_jobs/lock.rb b/lib/sidekiq_unique_jobs/lock.rb
index 29444b726..dcb2d3bac 100644
--- a/lib/sidekiq_unique_jobs/lock.rb
+++ b/lib/sidekiq_unique_jobs/lock.rb
@@ -62,13 +62,13 @@ def initialize(key, time: nil)
     #
     def lock(job_id, lock_info = {})
       redis do |conn|
-        conn.multi do
-          conn.set(key.digest, job_id)
-          conn.hset(key.locked, job_id, now_f)
+        conn.multi do |pipeline|
+          pipeline.set(key.digest, job_id)
+          pipeline.hset(key.locked, job_id, now_f)
           info.set(lock_info)
-          conn.zadd(key.digests, now_f, key.digest)
-          conn.zadd(key.changelog, now_f, changelog_json(job_id, "queue.lua", "Queued"))
-          conn.zadd(key.changelog, now_f, changelog_json(job_id, "lock.lua", "Locked"))
+          pipeline.zadd(key.digests, now_f, key.digest)
+          pipeline.zadd(key.changelog, now_f, changelog_json(job_id, "queue.lua", "Queued"))
+          pipeline.zadd(key.changelog, now_f, changelog_json(job_id, "lock.lua", "Locked"))
         end
       end
     end
diff --git a/lib/sidekiq_unique_jobs/sidekiq_unique_ext.rb b/lib/sidekiq_unique_jobs/sidekiq_unique_ext.rb
index f5168c8be..9a3fd699b 100644
--- a/lib/sidekiq_unique_jobs/sidekiq_unique_ext.rb
+++ b/lib/sidekiq_unique_jobs/sidekiq_unique_ext.rb
@@ -68,7 +68,7 @@ def delete(score, job_id)
     prepend UniqueExtension
   end
 
-  if Sidekiq.const_defined?("JobRecord")
+  if Sidekiq.const_defined?(:JobRecord)
     # See Sidekiq::Api
     class JobRecord
       #
diff --git a/lib/sidekiq_unique_jobs/timing.rb b/lib/sidekiq_unique_jobs/timing.rb
index cf42ef59c..0558ba6ab 100644
--- a/lib/sidekiq_unique_jobs/timing.rb
+++ b/lib/sidekiq_unique_jobs/timing.rb
@@ -48,7 +48,7 @@ def now_f
     # @return [Float]
     #
     def clock_stamp
-      if Process.const_defined?("CLOCK_MONOTONIC")
+      if Process.const_defined?(:CLOCK_MONOTONIC)
         Process.clock_gettime(Process::CLOCK_MONOTONIC)
       else
         now_f
diff --git a/lib/sidekiq_unique_jobs/web/helpers.rb b/lib/sidekiq_unique_jobs/web/helpers.rb
index 1adc7f35e..621168cae 100644
--- a/lib/sidekiq_unique_jobs/web/helpers.rb
+++ b/lib/sidekiq_unique_jobs/web/helpers.rb
@@ -27,7 +27,7 @@ module Helpers
       # @return [String] the file contents of the template
       #
       def unique_template(name)
-        File.open(unique_filename(name)).read
+        File.read(unique_filename(name))
       end
 
       #
diff --git a/spec/jobs/another_unique_job_job_spec.rb b/spec/jobs/another_unique_job_job_spec.rb
index be7f827f4..fb3eddc47 100644
--- a/spec/jobs/another_unique_job_job_spec.rb
+++ b/spec/jobs/another_unique_job_job_spec.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-if Sidekiq.const_defined?("JobRecord")
+if Sidekiq.const_defined?(:JobRecord)
   RSpec.describe AnotherUniqueJobJob do
     it_behaves_like "sidekiq with options" do
       let(:options) do
diff --git a/spec/sidekiq/api_spec.rb b/spec/sidekiq/api_spec.rb
index 12eef8c00..e6fdf8777 100644
--- a/spec/sidekiq/api_spec.rb
+++ b/spec/sidekiq/api_spec.rb
@@ -49,7 +49,7 @@
     end
   end
 
-  if Sidekiq.const_defined?("JobRecord")
+  if Sidekiq.const_defined?(:JobRecord)
     describe Sidekiq::JobRecord::UniqueExtension do
       it "deletes uniqueness lock on delete" do
         jid = JustAWorker.perform_async(roo: "baf")
diff --git a/spec/sidekiq_unique_jobs/lock/until_and_while_executing_spec.rb b/spec/sidekiq_unique_jobs/lock/until_and_while_executing_spec.rb
index df597fa29..6c11efb53 100644
--- a/spec/sidekiq_unique_jobs/lock/until_and_while_executing_spec.rb
+++ b/spec/sidekiq_unique_jobs/lock/until_and_while_executing_spec.rb
@@ -27,7 +27,7 @@
   let(:lock_timeout) { nil }
   let(:sleepy_time)  { 0 }
 
-  if Sidekiq.const_defined?("JobRecord")
+  if Sidekiq.const_defined?(:JobRecord)
     let(:worker_class) { AnotherUniqueJobJob }
   else
     let(:worker_class) { UntilAndWhileExecutingJob }
diff --git a/spec/sidekiq_unique_jobs/middleware/client_spec.rb b/spec/sidekiq_unique_jobs/middleware/client_spec.rb
index f3b044b04..3fff54b34 100644
--- a/spec/sidekiq_unique_jobs/middleware/client_spec.rb
+++ b/spec/sidekiq_unique_jobs/middleware/client_spec.rb
@@ -35,14 +35,6 @@
 
       expect(schedule_count).to eq(20)
     end
-
-    it "schedules allows jobs to be scheduled" do
-      [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20].each do |x|
-        PlainClass.delay_for(x, queue: "default", unique: :while_executing).run(1)
-      end
-
-      expect(schedule_count).to eq(20)
-    end
   end
 
   it "does not push duplicate messages when unique_args are filtered with a proc" do
@@ -81,12 +73,6 @@
     expect(queue_count("customqueue")).to eq(1)
   end
 
-  it "does not queue duplicates when when calling delay", sidekiq_ver: "< 7.0" do
-    Array.new(10) { PlainClass.delay(lock: :until_executed, queue: "customqueue").run(1) }
-
-    expect(queue_count("customqueue")).to eq(1)
-  end
-
   context "when class is not unique" do
     it "pushes duplicate messages" do
       Array.new(10) do
diff --git a/spec/sidekiq_unique_jobs/options_with_fallback_spec.rb b/spec/sidekiq_unique_jobs/options_with_fallback_spec.rb
index 3d1be33b2..e5ffdfcac 100644
--- a/spec/sidekiq_unique_jobs/options_with_fallback_spec.rb
+++ b/spec/sidekiq_unique_jobs/options_with_fallback_spec.rb
@@ -161,16 +161,5 @@ def initialize(item, options, worker_class = nil)
 
       it { is_expected.to eq(SimpleWorker.get_sidekiq_options) }
     end
-
-    context "when default_worker_options has been configured" do
-      let(:worker_class)           { PlainClass }
-      let(:default_worker_options) { { "lock" => :while_executing } }
-
-      it do
-        Sidekiq.use_options(default_worker_options) do
-          expect(class_options).to include(default_worker_options)
-        end
-      end
-    end
   end
 end
diff --git a/spec/sidekiq_unique_jobs/rspec/matchers/have_valid_sidekiq_options_spec.rb b/spec/sidekiq_unique_jobs/rspec/matchers/have_valid_sidekiq_options_spec.rb
index 9583aaba4..5996309fa 100644
--- a/spec/sidekiq_unique_jobs/rspec/matchers/have_valid_sidekiq_options_spec.rb
+++ b/spec/sidekiq_unique_jobs/rspec/matchers/have_valid_sidekiq_options_spec.rb
@@ -2,7 +2,7 @@
 
 RSpec.describe SidekiqUniqueJobs::RSpec::Matchers::HaveValidSidekiqOptions do
   describe "#matches?" do
-    if Sidekiq.const_defined?("JobRecord")
+    if Sidekiq.const_defined?(:JobRecord)
       context "when sidekiq options are valid" do
         it { expect(AnotherUniqueJob).to have_valid_sidekiq_options }
       end
diff --git a/spec/support/jobs/another_unique_job_job.rb b/spec/support/jobs/another_unique_job_job.rb
index 78541f111..f85ea3184 100644
--- a/spec/support/jobs/another_unique_job_job.rb
+++ b/spec/support/jobs/another_unique_job_job.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # :nocov:
-if Sidekiq.const_defined?("JobRecord")
+if Sidekiq.const_defined?(:JobRecord)
   require "sidekiq/job"
 
   class AnotherUniqueJobJob
diff --git a/spec/support/sidekiq_meta.rb b/spec/support/sidekiq_meta.rb
index fbfb06928..881c20c9e 100644
--- a/spec/support/sidekiq_meta.rb
+++ b/spec/support/sidekiq_meta.rb
@@ -25,11 +25,6 @@ def sidekiq_redis_driver
     Sidekiq.redis = redis
     flush_redis
 
-    if SidekiqUniqueJobs::VersionCheck.satisfied?(Sidekiq::VERSION, "< 7.0.0")
-      enable_delay = defined?(Sidekiq::Extensions) && Sidekiq::Extensions.respond_to?(:enable_delay!)
-      Sidekiq::Extensions.enable_delay! if enable_delay
-    end
-
     if (sidekiq = example.metadata.fetch(:sidekiq, :disable))
       sidekiq = :fake if sidekiq == true
       Sidekiq::Testing.send("#{sidekiq}!")
diff --git a/spec/support/simulate_lock.rb b/spec/support/simulate_lock.rb
index 9699586ab..0ad39729c 100644
--- a/spec/support/simulate_lock.rb
+++ b/spec/support/simulate_lock.rb
@@ -19,14 +19,14 @@ def lock_jid(key, jid, ttl: nil, lock_type: :until_executed)
 
   def simulate_lock(key, job_id)
     redis do |conn|
-      conn.multi do
-        conn.set(key.digest, job_id)
-        conn.lpush(key.queued, job_id)
-        conn.lpush(key.primed, job_id)
-        conn.hset(key.locked, job_id, now_f)
-        conn.zadd(key.digests, now_f, key.digest)
-        conn.zadd(key.changelog, now_f, changelog_entry(key, job_id, "queue.lua", "Queued"))
-        conn.zadd(key.changelog, now_f, changelog_entry(key, job_id, "lock.lua", "Locked"))
+      conn.multi do |pipeline|
+        pipeline.set(key.digest, job_id)
+        pipeline.lpush(key.queued, job_id)
+        pipeline.lpush(key.primed, job_id)
+        pipeline.hset(key.locked, job_id, now_f)
+        pipeline.zadd(key.digests, now_f, key.digest)
+        pipeline.zadd(key.changelog, now_f, changelog_entry(key, job_id, "queue.lua", "Queued"))
+        pipeline.zadd(key.changelog, now_f, changelog_entry(key, job_id, "lock.lua", "Locked"))
       end
     end
   end
diff --git a/spec/support/workers/plain_class.rb b/spec/support/workers/plain_class.rb
deleted file mode 100644
index 0949a68e0..000000000
--- a/spec/support/workers/plain_class.rb
+++ /dev/null
@@ -1,13 +0,0 @@
-# frozen_string_literal: true
-
-# :nocov:
-
-class PlainClass
-  def self.run(one)
-    [one]
-  end
-
-  def run(one)
-    [one]
-  end
-end
diff --git a/spec/workers/plain_class_spec.rb b/spec/workers/plain_class_spec.rb
deleted file mode 100644
index 01b3f037c..000000000
--- a/spec/workers/plain_class_spec.rb
+++ /dev/null
@@ -1,19 +0,0 @@
-# frozen_string_literal: true
-
-RSpec.describe PlainClass do
-  describe ".run" do
-    subject { described_class.run(arg) }
-
-    let(:arg) { "argument" }
-
-    it { is_expected.to eq(["argument"]) }
-  end
-
-  describe "#run" do
-    subject { described_class.new.run(arg) }
-
-    let(:arg) { "another argument" }
-
-    it { is_expected.to eq(["another argument"]) }
-  end
-end