diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9b0473130..daeb88792 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -45,6 +45,9 @@ jobs:
              RAILS_VERSION: 'main'
 
          # Rails 8.0 builds >= 3.2
+         - ruby: 3.4.0-rc1
+           env:
+             RAILS_VERSION: '~> 8.0.0'
          - ruby: 3.3
            env:
              RAILS_VERSION: '~> 8.0.0'
diff --git a/Gemfile b/Gemfile
index 5df5cc6e4..609895b36 100644
--- a/Gemfile
+++ b/Gemfile
@@ -16,6 +16,10 @@ gem 'ffi', '> 1.15.5'
 gem 'rake', '> 12'
 gem 'rubocop', '~> 1.28.2'
 
+if RUBY_VERSION.to_f > 3.3
+  gem 'cucumber', git: 'https://github.com/cucumber/cucumber-ruby', branch: 'main'
+end
+
 custom_gemfile = File.expand_path('Gemfile-custom', __dir__)
 eval_gemfile custom_gemfile if File.exist?(custom_gemfile)
 
diff --git a/lib/rspec/rails/matchers/have_enqueued_mail.rb b/lib/rspec/rails/matchers/have_enqueued_mail.rb
index cf4576e57..14f8f0111 100644
--- a/lib/rspec/rails/matchers/have_enqueued_mail.rb
+++ b/lib/rspec/rails/matchers/have_enqueued_mail.rb
@@ -129,13 +129,13 @@ def unmatching_mail_jobs
         end
 
         def unmatching_mail_jobs_message
-          msg = "Queued deliveries:"
+          messages = ["Queued deliveries:"]
 
           unmatching_mail_jobs.each do |job|
-            msg << "\n  #{mail_job_message(job)}"
+            messages << "  #{mail_job_message(job)}"
           end
 
-          msg
+          messages.join("\n")
         end
 
         def mail_job_message(job)
diff --git a/rspec-rails.gemspec b/rspec-rails.gemspec
index 788977e11..dd8e24ea6 100644
--- a/rspec-rails.gemspec
+++ b/rspec-rails.gemspec
@@ -55,5 +55,5 @@ Gem::Specification.new do |s|
 
   s.add_development_dependency 'ammeter',  '~> 1.1.5'
   s.add_development_dependency 'aruba',    '~> 0.14.12'
-  s.add_development_dependency 'cucumber', '~> 7.0'
+  s.add_development_dependency 'cucumber', '> 7.0'
 end
diff --git a/spec/rspec/rails/matchers/action_cable/have_broadcasted_to_spec.rb b/spec/rspec/rails/matchers/action_cable/have_broadcasted_to_spec.rb
index 67d4a51c7..fb37fec13 100644
--- a/spec/rspec/rails/matchers/action_cable/have_broadcasted_to_spec.rb
+++ b/spec/rspec/rails/matchers/action_cable/have_broadcasted_to_spec.rb
@@ -248,12 +248,16 @@ def broadcast(stream, msg)
     end
 
     it "has an appropriate description including the matcher's description when qualified with `#with` and a composable matcher" do
-      expect(
-        have_broadcasted_to("my_stream")
+      description = have_broadcasted_to("my_stream")
           .from_channel(channel)
           .with(a_hash_including(a: :b))
           .description
-      ).to eq("have broadcasted exactly 1 messages to my_stream with a hash including {:a => :b}")
+
+      if RUBY_VERSION >= '3.4'
+        expect(description).to eq("have broadcasted exactly 1 messages to my_stream with a hash including {a: :b}")
+      else
+        expect(description).to eq("have broadcasted exactly 1 messages to my_stream with a hash including {:a => :b}")
+      end
     end
   end
 end
diff --git a/spec/rspec/rails/matchers/be_a_new_spec.rb b/spec/rspec/rails/matchers/be_a_new_spec.rb
index 76906a56f..d24e3c699 100644
--- a/spec/rspec/rails/matchers/be_a_new_spec.rb
+++ b/spec/rspec/rails/matchers/be_a_new_spec.rb
@@ -71,10 +71,16 @@ def new_record?; true; end
           end
 
           it "fails" do
+            message =
+              if RUBY_VERSION >= '3.4'
+                "attribute {\"foo\" => (a string matching \"bar\")} was not set on #{record.inspect}"
+              else
+                "attribute {\"foo\"=>(a string matching \"bar\")} was not set on #{record.inspect}"
+              end
             expect {
               expect(record).to be_a_new(record.class).with(
                 foo: a_string_matching("bar"))
-            }.to raise_error("attribute {\"foo\"=>(a string matching \"bar\")} was not set on #{record.inspect}")
+            }.to raise_error(message)
           end
 
           context "matcher is wrong type" do
@@ -101,12 +107,18 @@ def new_record?; true; end
 
           context "only one matcher present in actual" do
             it "fails" do
+              message =
+                if RUBY_VERSION >= '3.4'
+                  "attribute {\"bar\" => (a string matching \"barn\")} was not set on #{record.inspect}"
+                else
+                  "attribute {\"bar\"=>(a string matching \"barn\")} was not set on #{record.inspect}"
+                end
               expect {
                 expect(record).to be_a_new(record.class).with(
                   foo: a_string_matching("foo"),
                   bar: a_string_matching("barn")
                 )
-              }.to raise_error("attribute {\"bar\"=>(a string matching \"barn\")} was not set on #{record.inspect}")
+              }.to raise_error(message)
             end
           end
         end
@@ -118,19 +130,29 @@ def new_record?; true; end
             expect(record).to be_a_new(record.class).with(zoo: 'zoo', car: 'car')
           }.to raise_error { |e|
             expect(e.message).to match(/attributes \{.*\} were not set on #{Regexp.escape record.inspect}/)
-            expect(e.message).to match(/"zoo"=>"zoo"/)
-            expect(e.message).to match(/"car"=>"car"/)
+            if RUBY_VERSION >= '3.4'
+              expect(e.message).to match(/"zoo" => "zoo"/)
+              expect(e.message).to match(/"car" => "car"/)
+            else
+              expect(e.message).to match(/"zoo"=>"zoo"/)
+              expect(e.message).to match(/"car"=>"car"/)
+            end
           }
         end
       end
 
       context "one attribute value not the same" do
         it "fails" do
+          message =
+            if RUBY_VERSION >= '3.4'
+              %(attribute {"foo" => "bar"} was not set on #{record.inspect})
+            else
+              %(attribute {"foo"=>"bar"} was not set on #{record.inspect})
+            end
+
           expect {
             expect(record).to be_a_new(record.class).with(foo: 'bar')
-          }.to raise_error(
-            %(attribute {"foo"=>"bar"} was not set on #{record.inspect})
-          )
+          }.to raise_error(message)
         end
       end
     end
@@ -166,20 +188,30 @@ def new_record?; false; end
             expect(record).to be_a_new(String).with(zoo: 'zoo', car: 'car')
           }.to raise_error { |e|
             expect(e.message).to match(/expected #{Regexp.escape record.inspect} to be a new String and attributes \{.*\} were not set on #{Regexp.escape record.inspect}/)
-            expect(e.message).to match(/"zoo"=>"zoo"/)
-            expect(e.message).to match(/"car"=>"car"/)
+            if RUBY_VERSION >= '3.4'
+              expect(e.message).to match(/"zoo" => "zoo"/)
+              expect(e.message).to match(/"car" => "car"/)
+            else
+              expect(e.message).to match(/"zoo"=>"zoo"/)
+              expect(e.message).to match(/"car"=>"car"/)
+            end
           }
         end
       end
 
       context "one attribute value not the same" do
         it "fails" do
+          message =
+            "expected #{record.inspect} to be a new String and " +
+            if RUBY_VERSION >= '3.4'
+              %(attribute {"foo" => "bar"} was not set on #{record.inspect})
+            else
+              %(attribute {"foo"=>"bar"} was not set on #{record.inspect})
+            end
+
           expect {
             expect(record).to be_a_new(String).with(foo: 'bar')
-          }.to raise_error(
-            "expected #{record.inspect} to be a new String and " +
-            %(attribute {"foo"=>"bar"} was not set on #{record.inspect})
-          )
+          }.to raise_error(message)
         end
       end
     end
diff --git a/spec/rspec/rails/matchers/be_routable_spec.rb b/spec/rspec/rails/matchers/be_routable_spec.rb
index c3a6a1b15..65edb2bb5 100644
--- a/spec/rspec/rails/matchers/be_routable_spec.rb
+++ b/spec/rspec/rails/matchers/be_routable_spec.rb
@@ -18,9 +18,17 @@
 
     it "fails if routes do not recognize the path" do
       allow(routes).to receive(:recognize_path) { raise ActionController::RoutingError, 'ignore' }
+
+      message =
+        if RUBY_VERSION >= '3.4'
+          /expected \{get: "\/a\/path"\} to be routable/
+        else
+          /expected \{:get=>"\/a\/path"\} to be routable/
+        end
+
       expect do
         expect({ get: "/a/path" }).to be_routable
-      end.to raise_error(/expected \{:get=>"\/a\/path"\} to be routable/)
+      end.to raise_error(message)
     end
   end
 
@@ -35,9 +43,17 @@
 
     it "fails if routes recognize the path" do
       allow(routes).to receive(:recognize_path) { { controller: "foo" } }
+
+      message =
+        if RUBY_VERSION >= '3.4'
+          /expected \{get: "\/a\/path"\} not to be routable, but it routes to \{controller: "foo"\}/
+        else
+          /expected \{:get=>"\/a\/path"\} not to be routable, but it routes to \{:controller=>"foo"\}/
+        end
+
       expect do
         expect({ get: "/a/path" }).not_to be_routable
-      end.to raise_error(/expected \{:get=>"\/a\/path"\} not to be routable, but it routes to \{:controller=>"foo"\}/)
+      end.to raise_error(message)
     end
   end
 end
diff --git a/spec/rspec/rails/matchers/route_to_spec.rb b/spec/rspec/rails/matchers/route_to_spec.rb
index ae49791f8..8b1d7836b 100644
--- a/spec/rspec/rails/matchers/route_to_spec.rb
+++ b/spec/rspec/rails/matchers/route_to_spec.rb
@@ -9,7 +9,15 @@ def assert_recognizes(*)
   it "provides a description" do
     matcher = route_to("these" => "options")
     matcher.matches?(get: "path")
-    expect(matcher.description).to eq("route {:get=>\"path\"} to {\"these\"=>\"options\"}")
+
+    description =
+      if RUBY_VERSION >= '3.4'
+        "route {get: \"path\"} to {\"these\" => \"options\"}"
+      else
+        "route {:get=>\"path\"} to {\"these\"=>\"options\"}"
+      end
+
+    expect(matcher.description).to eq(description)
   end
 
   it "delegates to assert_recognizes" do
@@ -107,9 +115,16 @@ def assert_recognizes(*)
   context "with should_not" do
     context "when assert_recognizes passes" do
       it "fails with custom message" do
+        message =
+          if RUBY_VERSION >= '3.4'
+            /expected \{get: "path"\} not to route to \{"these" => "options"\}/
+          else
+            /expected \{:get=>"path"\} not to route to \{"these"=>"options"\}/
+          end
+
         expect {
           expect({ get: "path" }).not_to route_to("these" => "options")
-        }.to raise_error(/expected \{:get=>"path"\} not to route to \{"these"=>"options"\}/)
+        }.to raise_error(message)
       end
     end
 
diff --git a/spec/sanity_check_spec.rb b/spec/sanity_check_spec.rb
index 4746a157e..7faef98a8 100644
--- a/spec/sanity_check_spec.rb
+++ b/spec/sanity_check_spec.rb
@@ -29,6 +29,7 @@ def with_clean_env
         .to match(/uninitialized constant RSpec::Support/)
         .or match(/undefined method `require_rspec_core' for RSpec::Support:Module/)
         .or match(/undefined method `require_rspec_core' for module RSpec::Support/)
+        .or match(/undefined method 'require_rspec_core' for module RSpec::Support/)
 
       expect($?.exitstatus).to eq(1)
     end