diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7101817c51..fa880114d9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,6 +16,31 @@ jobs:
       fail-fast: false
       matrix:
        include:
+         # Rails Master (7.0) builds >= 2.7
+         - ruby: 3.0
+           allow_failure: true
+           env:
+             RAILS_VERSION: 'master'
+         - ruby: 2.7
+           allow_failure: true
+           env:
+             RAILS_VERSION: 'master'
+
+         # Rails 6.1 builds >= 2.5
+         - ruby: 3.0
+           allow_failure: true
+           env:
+             RAILS_VERSION: '~> 6.1.0'
+         - ruby: 2.7
+           env:
+             RAILS_VERSION: '~> 6.1.0'
+         - ruby: 2.6
+           env:
+             RAILS_VERSION: '~> 6.1.0'
+         - ruby: 2.5
+           env:
+             RAILS_VERSION: '~> 6.1.0'
+
          # Rails 6.0 builds >= 2.5.0
          - ruby: 3.0
            env:
diff --git a/.travis.yml b/.travis.yml
index 4012daadfd..1d48088034 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -38,6 +38,14 @@ script: "script/run_build 2>&1"
 
 matrix:
   include:
+    # Rails 6.1 builds >= 2.5
+    - jdk: oraclejdk11
+      env:
+        - RAILS_VERSION='master'
+        - JRUBY_OPT=--dev
+        - JAVA_OPTS="--add-opens java.base/sun.nio.ch=org.jruby.dist --add-opens java.base/java.io=org.jruby.dist --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.security=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.security.cert=ALL-UNNAMED --add-opens=java.base/java.util.zip=ALL-UNNAMED --add-opens=java.base/java.lang.reflect=ALL-UNNAMED --add-opens=java.base/java.util.regex=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED  --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/javax.crypto=ALL-UNNAMED --add-opens=java.management/sun.management=ALL-UNNAMED"
+
+    # Rails 6.0 builds >= 2.5.0
     - rvm: jruby-head
       jdk: oraclejdk11
       env:
diff --git a/Changelog.md b/Changelog.md
index a3df08ee52..864a7a816b 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,5 +1,10 @@
+### Development
+[Full Changelog](https://github.com/rspec/rspec-rails/compare/v4.1.0...main)
+
+* Support new #file_fixture_path and new fixture test support code. (Jon Rowe, #2398)
+* Support for Rails 6.1. (Benoit Tigeot, Jon Rowe, Phil Pirozhkov, and more #2398)
+
 ### 4.1.0 / 2021-03-06
-[Full Changelog](https://github.com/rspec/rspec-rails/compare/v4.0.2...v4.1.0)
 
 Enhancements:
 
@@ -26,6 +31,7 @@ Bug Fixes:
   (Phil Pirozhkov, Jon Rowe, #2353, #2354)
 * Remove old #fixture_path feature detection code which broke under newer Rails.
   (Koen Punt, Jon Rowe, #2370)
+* Fix an error when `use_active_record` is `false` (Phil Pirozhkov, #2423)
 
 ### 4.0.1 / 2020-05-16
 [Full Changelog](https://github.com/rspec/rspec-rails/compare/v4.0.0...v4.0.1)
diff --git a/Gemfile-rails-dependencies b/Gemfile-rails-dependencies
index 5b3ebda404..03f75abfb2 100644
--- a/Gemfile-rails-dependencies
+++ b/Gemfile-rails-dependencies
@@ -1,7 +1,7 @@
 version_file = File.expand_path("../.rails-version", __FILE__)
 
 case version = ENV['RAILS_VERSION'] || (File.exist?(version_file) && File.read(version_file).chomp) || ''
-when /main/
+when /master/
   gem "rails", :git => "https://github.com/rails/rails.git"
   gem "arel", :git => "https://github.com/rails/arel.git"
   gem "journey", :git => "https://github.com/rails/journey.git"
diff --git a/Rakefile b/Rakefile
index f68cb64a6f..ac5a7b39c3 100644
--- a/Rakefile
+++ b/Rakefile
@@ -27,10 +27,13 @@ RSpec::Core::RakeTask.new(:spec) do |t|
 end
 
 Cucumber::Rake::Task.new(:cucumber) do |t|
-  version = ENV.fetch("RAILS_VERSION", "~> 6.0.0")[/\d[\.-]\d/].tr('-', '.')
-  if version == "main" || version.nil?
-    version = Float::INFINITY
-  end
+  string_version = ENV.fetch("RAILS_VERSION", "~> 6.0.0")
+  version =
+    if string_version == "master" || string_version.nil?
+      Float::INFINITY
+    else
+      string_version[/\d[\.-]\d/].tr('-', '.')
+    end
   tags = []
 
   if version.to_f >= 5.1
diff --git a/example_app_generator/generate_action_mailer_specs.rb b/example_app_generator/generate_action_mailer_specs.rb
index 13a1f0a4c0..06833fc1a5 100644
--- a/example_app_generator/generate_action_mailer_specs.rb
+++ b/example_app_generator/generate_action_mailer_specs.rb
@@ -14,15 +14,20 @@
       end
     end
   CODE
-  gsub_file 'config/initializers/action_mailer.rb',
-            /ExampleApp/,
-            Rails.application.class.parent.to_s
+
+  rails_parent =
+    if Rails.version.to_f >= 6.0
+      Rails.application.class.module_parent.to_s
+    else
+      Rails.application.class.parent.to_s
+    end
+
+  gsub_file 'config/initializers/action_mailer.rb', /ExampleApp/, rails_parent
 
   copy_file 'spec/support/default_preview_path'
   chmod 'spec/support/default_preview_path', 0755
-  gsub_file 'spec/support/default_preview_path',
-            /ExampleApp/,
-            Rails.application.class.parent.to_s
+  gsub_file 'spec/support/default_preview_path', /ExampleApp/, rails_parent
+
   if skip_active_record?
     comment_lines 'spec/support/default_preview_path', /active_record/
     comment_lines 'spec/support/default_preview_path', /active_storage/
diff --git a/features/controller_specs/anonymous_controller.feature b/features/controller_specs/anonymous_controller.feature
index 7892b4dfac..9baf73fb8d 100644
--- a/features/controller_specs/anonymous_controller.feature
+++ b/features/controller_specs/anonymous_controller.feature
@@ -101,6 +101,8 @@ Feature: anonymous controller
     When I run `rspec spec`
     Then the examples should all pass
 
+  # Deprecated support removed in https://github.com/rails/rails/commit/d52d7739468153bd6cb7c629f60bd5cd7ebea3eb
+  @rails_pre_6
   Scenario: Specify error handling in `ApplicationController` with render :file
     Given a file named "spec/controllers/application_controller_spec.rb" with:
       """ruby
diff --git a/lib/rspec/rails/fixture_file_upload_support.rb b/lib/rspec/rails/fixture_file_upload_support.rb
index bcbc733d74..ef4989c653 100644
--- a/lib/rspec/rails/fixture_file_upload_support.rb
+++ b/lib/rspec/rails/fixture_file_upload_support.rb
@@ -6,21 +6,42 @@ module FixtureFileUploadSupport
 
     private
 
-      def rails_fixture_file_wrapper
-        RailsFixtureFileWrapper.fixture_path = nil
-        resolved_fixture_path =
-          if respond_to?(:fixture_path) && !fixture_path.nil?
-            fixture_path.to_s
-          else
-            (RSpec.configuration.fixture_path || '').to_s
-          end
-        RailsFixtureFileWrapper.fixture_path = File.join(resolved_fixture_path, '') unless resolved_fixture_path.strip.empty?
-        RailsFixtureFileWrapper.instance
+      # In Rails 6.2 fixture file path needs to be relative to `file_fixture_path` instead, this change
+      # was brought in with a deprecation warning on 6.1. In Rails 6.2 expect to rework this to remove
+      # the old accessor.
+      if ::Rails.version.to_f >= 6.1
+        def rails_fixture_file_wrapper
+          RailsFixtureFileWrapper.file_fixture_path = nil
+          resolved_fixture_path =
+            if respond_to?(:file_fixture_path) && !file_fixture_path.nil?
+              file_fixture_path.to_s
+            else
+              (RSpec.configuration.fixture_path || '').to_s
+            end
+          RailsFixtureFileWrapper.file_fixture_path = File.join(resolved_fixture_path, '') unless resolved_fixture_path.strip.empty?
+          RailsFixtureFileWrapper.instance
+        end
+      else
+        def rails_fixture_file_wrapper
+          RailsFixtureFileWrapper.fixture_path = nil
+          resolved_fixture_path =
+            if respond_to?(:fixture_path) && !fixture_path.nil?
+              fixture_path.to_s
+            else
+              (RSpec.configuration.fixture_path || '').to_s
+            end
+          RailsFixtureFileWrapper.fixture_path = File.join(resolved_fixture_path, '') unless resolved_fixture_path.strip.empty?
+          RailsFixtureFileWrapper.instance
+        end
       end
 
       class RailsFixtureFileWrapper
         include ActionDispatch::TestProcess if defined?(ActionDispatch::TestProcess)
 
+        if ::Rails.version.to_f >= 6.1
+          include ActiveSupport::Testing::FileFixtures
+        end
+
         class << self
           attr_accessor :fixture_path
 
diff --git a/lib/rspec/rails/matchers/action_mailbox.rb b/lib/rspec/rails/matchers/action_mailbox.rb
index c5392cb225..de50c69143 100644
--- a/lib/rspec/rails/matchers/action_mailbox.rb
+++ b/lib/rspec/rails/matchers/action_mailbox.rb
@@ -22,11 +22,20 @@ def initialize(message)
             @inbound_email = create_inbound_email(message)
           end
 
-          def matches?(mailbox)
-            @mailbox  = mailbox
-            @receiver = ApplicationMailbox.router.send(:match_to_mailbox, inbound_email)
+          if defined?(::ApplicationMailbox) && ::ApplicationMailbox.router.respond_to?(:mailbox_for)
+            def matches?(mailbox)
+              @mailbox  = mailbox
+              @receiver = ApplicationMailbox.router.mailbox_for(inbound_email)
 
-            @receiver == @mailbox
+              @receiver == @mailbox
+            end
+          else
+            def matches?(mailbox)
+              @mailbox  = mailbox
+              @receiver = ApplicationMailbox.router.send(:match_to_mailbox, inbound_email)
+
+              @receiver == @mailbox
+            end
           end
 
           def failure_message
@@ -41,7 +50,7 @@ def failure_message_when_negated
             "expected #{describe_inbound_email} not to route to #{mailbox}"
           end
 
-        private
+          private
 
           attr_reader :inbound_email, :mailbox, :receiver
 
diff --git a/spec/rspec/rails/example/controller_example_group_spec.rb b/spec/rspec/rails/example/controller_example_group_spec.rb
index 329626191b..56b53049d1 100644
--- a/spec/rspec/rails/example/controller_example_group_spec.rb
+++ b/spec/rspec/rails/example/controller_example_group_spec.rb
@@ -36,7 +36,14 @@ def my_helper
             "other_value"
           end
         end
-        config.include mod
+
+        # Rails 6.1 removes config from ./activerecord/lib/active_record/test_fixtures.rb
+        if respond_to?(:config)
+          config.include mod
+        else
+          ActiveRecord::Base.include mod
+        end
+
         group.class_exec do
           let(:my_helper) { "my_value" }
         end
diff --git a/spec/rspec/rails/example/view_example_group_spec.rb b/spec/rspec/rails/example/view_example_group_spec.rb
index f46f7feb04..9b4dafcc74 100644
--- a/spec/rspec/rails/example/view_example_group_spec.rb
+++ b/spec/rspec/rails/example/view_example_group_spec.rb
@@ -13,6 +13,7 @@ module ::Namespaced; module ThingsHelper; end; end
         group = RSpec::Core::ExampleGroup.describe('things/show.html.erb') do
           def self.helper(*); end # Stub method
         end
+        allow(group).to receive(:helper)
         expect(group).to receive(:helper).with(ThingsHelper)
         group.class_exec do
           include ViewExampleGroup
@@ -23,6 +24,7 @@ def self.helper(*); end # Stub method
         group = RSpec::Core::ExampleGroup.describe('namespaced/things/show.html.erb') do
           def self.helper(*); end # Stub method
         end
+        allow(group).to receive(:helper)
         expect(group).to receive(:helper).with(Namespaced::ThingsHelper)
         group.class_exec do
           include ViewExampleGroup
@@ -66,6 +68,7 @@ module ::ApplicationHelper; end
           group = RSpec::Core::ExampleGroup.describe('bars/new.html.erb') do
             def self.helper(*); end # Stub method
           end
+          allow(group).to receive(:helper)
           expect(group).to receive(:helper).with(ApplicationHelper)
           group.class_exec do
             include ViewExampleGroup
diff --git a/spec/rspec/rails/fixture_file_upload_support_spec.rb b/spec/rspec/rails/fixture_file_upload_support_spec.rb
index d7be688d19..af074704dd 100644
--- a/spec/rspec/rails/fixture_file_upload_support_spec.rb
+++ b/spec/rspec/rails/fixture_file_upload_support_spec.rb
@@ -3,33 +3,43 @@ module RSpec::Rails
     context 'with fixture path set in config' do
       it 'resolves fixture file' do
         RSpec.configuration.fixture_path = File.dirname(__FILE__)
-        expect(fixture_file_upload_resolved('fixture_file_upload_support_spec.rb').run).to be true
+        expect_to_pass fixture_file_upload_resolved('fixture_file_upload_support_spec.rb')
       end
 
       it 'resolves supports `Pathname` objects' do
         RSpec.configuration.fixture_path = Pathname(File.dirname(__FILE__))
-        expect(fixture_file_upload_resolved('fixture_file_upload_support_spec.rb').run).to be true
+        expect_to_pass fixture_file_upload_resolved('fixture_file_upload_support_spec.rb')
       end
     end
 
     context 'with fixture path set in spec' do
       it 'resolves fixture file' do
-        expect(fixture_file_upload_resolved('fixture_file_upload_support_spec.rb', File.dirname(__FILE__)).run).to be true
+        expect_to_pass fixture_file_upload_resolved('fixture_file_upload_support_spec.rb', File.dirname(__FILE__))
       end
     end
 
     context 'with fixture path not set' do
       it 'resolves fixture using relative path' do
         RSpec.configuration.fixture_path = nil
-        expect(fixture_file_upload_resolved('spec/rspec/rails/fixture_file_upload_support_spec.rb').run).to be true
+        expect_to_pass fixture_file_upload_resolved('spec/rspec/rails/fixture_file_upload_support_spec.rb')
       end
     end
 
+    def expect_to_pass(group)
+      result = group.run(failure_reporter)
+      failure_reporter.exceptions.map { |e| raise e }
+      expect(result).to be true
+    end
+
     def fixture_file_upload_resolved(fixture_name, fixture_path = nil)
       RSpec::Core::ExampleGroup.describe do
         include RSpec::Rails::FixtureFileUploadSupport
 
-        self.fixture_path = fixture_path
+        if ::Rails.version.to_f >= 6.1
+          self.file_fixture_path = fixture_path
+        else
+          self.fixture_path = fixture_path
+        end
 
         it 'supports fixture file upload' do
           file = fixture_file_upload(fixture_name)
diff --git a/spec/rspec/rails/matchers/active_job_spec.rb b/spec/rspec/rails/matchers/active_job_spec.rb
index 896cd7db1e..02c3132016 100644
--- a/spec/rspec/rails/matchers/active_job_spec.rb
+++ b/spec/rspec/rails/matchers/active_job_spec.rb
@@ -702,4 +702,16 @@ def self.name; "LoggingJob"; end
       }.to raise_error(/expected to perform exactly 1 jobs, but performed 0/)
     end
   end
+
+  describe 'Active Job test helpers' do
+    include ActiveJob::TestHelper
+
+    it 'does not raise that "assert_nothing_raised" is undefined' do
+      expect {
+        perform_enqueued_jobs do
+          :foo
+        end
+      }.to_not raise_error
+    end
+  end
 end