diff --git a/.github/workflows/sorbet.yml b/.github/workflows/sorbet.yml
index d87bf16cdc..72902fade0 100644
--- a/.github/workflows/sorbet.yml
+++ b/.github/workflows/sorbet.yml
@@ -16,7 +16,7 @@ permissions:
 jobs:
   tapioca:
     if: github.repository == 'Homebrew/brew'
-    runs-on: macos-latest
+    runs-on: macos-12
     steps:
       - name: Set up Homebrew
         id: set-up-homebrew
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 7e70a50763..e01422163a 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -49,7 +49,7 @@ jobs:
           vale docs/
 
   tap-syntax:
-    name: tap syntax (Linux)
+    name: tap syntax
     needs: syntax
     if: startsWith(github.repository, 'Homebrew/')
     runs-on: ubuntu-22.04
@@ -145,7 +145,7 @@ jobs:
                                          homebrew/cask-versions
 
   vendored-gems:
-    name: vendored gems (Linux)
+    name: vendored gems
     runs-on: ubuntu-22.04
     steps:
       - name: Set up Homebrew
@@ -222,16 +222,23 @@ jobs:
   tests:
     name: ${{ matrix.name }}
     needs: syntax
-    runs-on: ubuntu-22.04
+    runs-on: ${{ matrix.runs-on }}
     strategy:
       matrix:
         include:
           - name: tests (no-compatibility mode)
             test-flags: --no-compat --online --coverage
+            runs-on: ubuntu-22.04
           - name: tests (generic OS)
             test-flags: --generic --online --coverage
-          - name: tests (Linux)
+            runs-on: ubuntu-22.04
+          - name: tests (Ubuntu 22.04)
             test-flags: --online --coverage
+            runs-on: ubuntu-22.04
+          # Enable later once this can be fixed.
+          # - name: tests (Ubuntu 18.04)
+          #   test-flags: --online --coverage
+          #   runs-on: ubuntu-18.04
     steps:
       - name: Set up Homebrew
         id: set-up-homebrew
@@ -274,10 +281,19 @@ jobs:
           files: Library/Homebrew/test/coverage/coverage.xml
 
   test-default-formula-linux:
-    name: test default formula (Linux)
-    runs-on: ubuntu-22.04
+    name: ${{ matrix.name }}
+    runs-on: ${{ matrix.runs-on }}
     env:
       HOMEBREW_BOOTSNAP: 1
+    strategy:
+      matrix:
+        include:
+          - name: test default formula (Ubuntu 22.04)
+            test-flags: --online --coverage
+            runs-on: ubuntu-22.04
+          - name: test default formula (Ubuntu 18.04)
+            test-flags: --online --coverage
+            runs-on: ubuntu-18.04
     steps:
       - name: Set up Homebrew
         id: set-up-homebrew
@@ -291,7 +307,7 @@ jobs:
     name: test everything (macOS)
     needs: syntax
     if: startsWith(github.repository, 'Homebrew/')
-    runs-on: macos-latest
+    runs-on: macos-12
     env:
       HOMEBREW_BOOTSNAP: 1
     steps:
diff --git a/.github/workflows/vendor-gems.yml b/.github/workflows/vendor-gems.yml
index 00a12b3127..08ec0ded89 100644
--- a/.github/workflows/vendor-gems.yml
+++ b/.github/workflows/vendor-gems.yml
@@ -21,7 +21,7 @@ jobs:
           contains(github.event.pull_request.title, '/Library/Homebrew')
         )
       )
-    runs-on: macos-latest
+    runs-on: macos-12
     steps:
       - name: Set up Homebrew
         id: set-up-homebrew
diff --git a/Library/Homebrew/Gemfile.lock b/Library/Homebrew/Gemfile.lock
index f10a0c35b1..b591ab4a9b 100644
--- a/Library/Homebrew/Gemfile.lock
+++ b/Library/Homebrew/Gemfile.lock
@@ -67,7 +67,7 @@ GEM
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     parallel (1.22.1)
-    parallel_tests (3.12.1)
+    parallel_tests (3.13.0)
       parallel
     parlour (8.0.0)
       commander (~> 4.5)
diff --git a/Library/Homebrew/dev-cmd/dispatch-build-bottle.rb b/Library/Homebrew/dev-cmd/dispatch-build-bottle.rb
index 4fd2780245..7385e5a8ba 100644
--- a/Library/Homebrew/dev-cmd/dispatch-build-bottle.rb
+++ b/Library/Homebrew/dev-cmd/dispatch-build-bottle.rb
@@ -69,7 +69,7 @@ module Homebrew
     end
 
     if args.linux?
-      runners << "ubuntu-latest"
+      runners << "ubuntu-22.04"
     elsif args.linux_self_hosted?
       runners << "linux-self-hosted-1"
     end
diff --git a/Library/Homebrew/dev-cmd/tap-new.rb b/Library/Homebrew/dev-cmd/tap-new.rb
index f09775fd0b..54f9bfad50 100644
--- a/Library/Homebrew/dev-cmd/tap-new.rb
+++ b/Library/Homebrew/dev-cmd/tap-new.rb
@@ -74,7 +74,7 @@ module Homebrew
         test-bot:
           strategy:
             matrix:
-              os: [ubuntu-latest, macos-latest]
+              os: [ubuntu-22.04, macos-12]
           runs-on: ${{ matrix.os }}
           steps:
             - name: Set up Homebrew
@@ -119,7 +119,7 @@ module Homebrew
       jobs:
         pr-pull:
           if: contains(github.event.pull_request.labels.*.name, '#{label}')
-          runs-on: ubuntu-latest
+          runs-on: ubuntu-22.04
           steps:
             - name: Set up Homebrew
               uses: Homebrew/actions/setup-homebrew@master
diff --git a/Library/Homebrew/extend/os/linux/install.rb b/Library/Homebrew/extend/os/linux/install.rb
index 6bf944c08e..2202386424 100644
--- a/Library/Homebrew/extend/os/linux/install.rb
+++ b/Library/Homebrew/extend/os/linux/install.rb
@@ -20,9 +20,6 @@ module Homebrew
     ].freeze
     private_constant :DYNAMIC_LINKERS
 
-    PREFERRED_GCC_RUNTIME_VERSION = OS::LINUX_PREFERRED_GCC_RUNTIME_FORMULA.split("@").last.freeze
-    private_constant :PREFERRED_GCC_RUNTIME_VERSION
-
     # We link GCC runtime libraries that are not specificaly used for Fortran,
     # which are linked by the GCC formula.  We only use the versioned shared libraries
     # as the other shared and static libraries are only used at build time where
@@ -97,11 +94,13 @@ module Homebrew
 
         # Add gcc to ld search paths
         ld_gcc_conf = ld_so_conf_d/"50-homebrew-preferred-gcc.conf"
-        unless ld_gcc_conf.exist?
-          ld_gcc_conf.atomic_write <<~EOS
-            # This file is generated by Homebrew. Do not modify.
-            #{gcc_opt_prefix}/lib/gcc/#{PREFERRED_GCC_RUNTIME_VERSION}
-          EOS
+        ld_gcc_conf_content = <<~EOS
+          # This file is generated by Homebrew. Do not modify.
+          #{gcc_opt_prefix}/lib/gcc/current
+        EOS
+
+        if !ld_gcc_conf.exist? || (ld_gcc_conf.read != ld_gcc_conf_content)
+          ld_gcc_conf.atomic_write ld_gcc_conf_content
           FileUtils.chmod "u=rw,go-wx", ld_gcc_conf
 
           FileUtils.rm_f HOMEBREW_PREFIX/"etc/ld.so.cache"
@@ -118,7 +117,7 @@ module Homebrew
           # Remove legacy symlinks
           FileUtils.rm gcc_library_symlink if gcc_library_symlink.symlink?
         else
-          gcc_library = gcc_opt_prefix/"lib/gcc/#{PREFERRED_GCC_RUNTIME_VERSION}/#{library}"
+          gcc_library = gcc_opt_prefix/"lib/gcc/current/#{library}"
           # Skip if the link target doesn't exist.
           next unless gcc_library.readable?
 
diff --git a/Library/Homebrew/os.rb b/Library/Homebrew/os.rb
index a36363695f..13ee649519 100644
--- a/Library/Homebrew/os.rb
+++ b/Library/Homebrew/os.rb
@@ -51,7 +51,7 @@ module OS
   LINUX_GLIBC_NEXT_CI_VERSION = "2.35"
   LINUX_GCC_CI_VERSION = "11.0"
   LINUX_PREFERRED_GCC_COMPILER_FORMULA = "gcc@11" # https://packages.ubuntu.com/jammy/gcc
-  LINUX_PREFERRED_GCC_RUNTIME_FORMULA = "gcc@12" # https://packages.ubuntu.com/jammy/libstdc++6
+  LINUX_PREFERRED_GCC_RUNTIME_FORMULA = "gcc"
 
   if OS.mac?
     require "os/mac"
diff --git a/Library/Homebrew/sorbet/rbi/gems/parallel_tests@3.12.1.rbi b/Library/Homebrew/sorbet/rbi/gems/parallel_tests@3.13.0.rbi
similarity index 100%
rename from Library/Homebrew/sorbet/rbi/gems/parallel_tests@3.12.1.rbi
rename to Library/Homebrew/sorbet/rbi/gems/parallel_tests@3.13.0.rbi
diff --git a/Library/Homebrew/sorbet/rbi/hidden-definitions/hidden.rbi b/Library/Homebrew/sorbet/rbi/hidden-definitions/hidden.rbi
index edc5f3f69c..805375a547 100644
--- a/Library/Homebrew/sorbet/rbi/hidden-definitions/hidden.rbi
+++ b/Library/Homebrew/sorbet/rbi/hidden-definitions/hidden.rbi
@@ -1598,8 +1598,6 @@ end
 class Errno::EBADRPC
 end
 
-Errno::ECAPMODE = Errno::NOERROR
-
 Errno::EDEADLOCK = Errno::NOERROR
 
 class Errno::EDEVERR
@@ -1620,13 +1618,6 @@ end
 
 Errno::EIPSEC = Errno::NOERROR
 
-class Errno::ELAST
-  Errno = ::T.let(nil, ::T.untyped)
-end
-
-class Errno::ELAST
-end
-
 class Errno::ENEEDAUTH
   Errno = ::T.let(nil, ::T.untyped)
 end
@@ -1648,8 +1639,6 @@ end
 class Errno::ENOPOLICY
 end
 
-Errno::ENOTCAPABLE = Errno::NOERROR
-
 class Errno::ENOTSUP
   Errno = ::T.let(nil, ::T.untyped)
 end
@@ -1692,7 +1681,12 @@ end
 class Errno::EPWROFF
 end
 
-Errno::EQFULL = Errno::ELAST
+class Errno::EQFULL
+  Errno = ::T.let(nil, ::T.untyped)
+end
+
+class Errno::EQFULL
+end
 
 class Errno::ERPCMISMATCH
   Errno = ::T.let(nil, ::T.untyped)
@@ -3028,6 +3022,14 @@ class Integer
   def to_bn(); end
 end
 
+class JSON::Ext::Generator::State
+  def escape_slash(); end
+
+  def escape_slash=(escape_slash); end
+
+  def escape_slash?(); end
+end
+
 class JSON::Ext::Generator::State
   def self.from_state(arg); end
 end
@@ -3534,6 +3536,7 @@ class Object
   def stub(name, val_or_callable, *block_args, **block_kwargs, &block); end
 
   def to_yaml(options=T.unsafe(nil)); end
+  APPLE_GEM_HOME = ::T.let(nil, ::T.untyped)
   APPLY_A = ::T.let(nil, ::T.untyped)
   APPLY_B = ::T.let(nil, ::T.untyped)
   APPLY_C = ::T.let(nil, ::T.untyped)
@@ -3614,6 +3617,8 @@ class Object
   RUBY_DESCRIPTION = ::T.let(nil, ::T.untyped)
   RUBY_ENGINE = ::T.let(nil, ::T.untyped)
   RUBY_ENGINE_VERSION = ::T.let(nil, ::T.untyped)
+  RUBY_FRAMEWORK = ::T.let(nil, ::T.untyped)
+  RUBY_FRAMEWORK_VERSION = ::T.let(nil, ::T.untyped)
   RUBY_PATCHLEVEL = ::T.let(nil, ::T.untyped)
   RUBY_PATH = ::T.let(nil, ::T.untyped)
   RUBY_PLATFORM = ::T.let(nil, ::T.untyped)
@@ -3665,11 +3670,7 @@ class OpenSSL::KDF::KDFError
 end
 
 module OpenSSL::KDF
-  def self.hkdf(*arg); end
-
   def self.pbkdf2_hmac(*arg); end
-
-  def self.scrypt(*arg); end
 end
 
 class OpenSSL::OCSP::Request
@@ -3678,29 +3679,20 @@ end
 
 OpenSSL::PKCS7::Signer = OpenSSL::PKCS7::SignerInfo
 
-class OpenSSL::PKey::EC
-  EXPLICIT_CURVE = ::T.let(nil, ::T.untyped)
-end
-
 class OpenSSL::PKey::EC::Point
   def to_octet_string(arg); end
 end
 
 module OpenSSL::SSL
-  OP_ALLOW_NO_DHE_KEX = ::T.let(nil, ::T.untyped)
   OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION = ::T.let(nil, ::T.untyped)
   OP_CRYPTOPRO_TLSEXT_BUG = ::T.let(nil, ::T.untyped)
   OP_LEGACY_SERVER_CONNECT = ::T.let(nil, ::T.untyped)
-  OP_NO_ENCRYPT_THEN_MAC = ::T.let(nil, ::T.untyped)
-  OP_NO_RENEGOTIATION = ::T.let(nil, ::T.untyped)
-  OP_NO_TLSv1_3 = ::T.let(nil, ::T.untyped)
   OP_SAFARI_ECDHE_ECDSA_BUG = ::T.let(nil, ::T.untyped)
   OP_TLSEXT_PADDING = ::T.let(nil, ::T.untyped)
   SSL2_VERSION = ::T.let(nil, ::T.untyped)
   SSL3_VERSION = ::T.let(nil, ::T.untyped)
   TLS1_1_VERSION = ::T.let(nil, ::T.untyped)
   TLS1_2_VERSION = ::T.let(nil, ::T.untyped)
-  TLS1_3_VERSION = ::T.let(nil, ::T.untyped)
   TLS1_VERSION = ::T.let(nil, ::T.untyped)
 end
 
@@ -3713,8 +3705,6 @@ class OpenSSL::SSL::SSLContext
 
   def alpn_select_cb=(alpn_select_cb); end
 
-  def enable_fallback_scsv(); end
-
   def max_version=(version); end
 
   def min_version=(version); end
@@ -6272,6 +6262,7 @@ class Socket
   IPV6_PATHMTU = ::T.let(nil, ::T.untyped)
   IPV6_RECVPATHMTU = ::T.let(nil, ::T.untyped)
   IPV6_USE_MIN_MTU = ::T.let(nil, ::T.untyped)
+  IP_DONTFRAG = ::T.let(nil, ::T.untyped)
   IP_PORTRANGE = ::T.let(nil, ::T.untyped)
   IP_RECVDSTADDR = ::T.let(nil, ::T.untyped)
   IP_RECVIF = ::T.let(nil, ::T.untyped)
@@ -6363,6 +6354,7 @@ module Socket::Constants
   IPV6_PATHMTU = ::T.let(nil, ::T.untyped)
   IPV6_RECVPATHMTU = ::T.let(nil, ::T.untyped)
   IPV6_USE_MIN_MTU = ::T.let(nil, ::T.untyped)
+  IP_DONTFRAG = ::T.let(nil, ::T.untyped)
   IP_PORTRANGE = ::T.let(nil, ::T.untyped)
   IP_RECVDSTADDR = ::T.let(nil, ::T.untyped)
   IP_RECVIF = ::T.let(nil, ::T.untyped)
diff --git a/Library/Homebrew/vendor/bundle/bundler/setup.rb b/Library/Homebrew/vendor/bundle/bundler/setup.rb
index a9e66b4cfc..bc852753d8 100644
--- a/Library/Homebrew/vendor/bundle/bundler/setup.rb
+++ b/Library/Homebrew/vendor/bundle/bundler/setup.rb
@@ -57,7 +57,7 @@ $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/mechanize-2.8.5/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/method_source-1.0.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/mustache-1.1.1/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/parallel-1.22.1/lib"
-$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/parallel_tests-3.12.1/lib"
+$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/parallel_tests-3.13.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/parser-3.1.2.1/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/rainbow-3.1.1/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/sorbet-runtime-0.5.10175/lib"
diff --git a/README.md b/README.md
index 2f36008b47..c2298a7cec 100644
--- a/README.md
+++ b/README.md
@@ -85,6 +85,6 @@ Flaky test detection and tracking is provided by [BuildPulse](https://buildpulse
 [![DNSimple](https://cdn.dnsimple.com/assets/resolving-with-us/logo-light.png)](https://dnsimple.com/resolving/homebrew#gh-light-mode-only)
 [![DNSimple](https://cdn.dnsimple.com/assets/resolving-with-us/logo-dark.png)](https://dnsimple.com/resolving/homebrew#gh-dark-mode-only)
 
-Homebrew is generously supported by [GitHub](https://github.com/github), [Custom Ink](https://github.com/customink), [Randy Reddig](https://github.com/ydnar), [Christian (Xian) M. Lilley](https://github.com/xml), [Codecademy](https://github.com/Codecademy), [David Fernandez](https://github.com/lidstromberg), [Appwrite](https://github.com/appwrite), [Mercedes-Benz Group](https://github.com/mercedes-benz), [embark-studios](https://github.com/embark-studios) and many other users and organisations via [GitHub Sponsors](https://github.com/sponsors/Homebrew).
+Homebrew is generously supported by [GitHub](https://github.com/github), [Custom Ink](https://github.com/customink), [Randy Reddig](https://github.com/ydnar), [Codecademy](https://github.com/Codecademy), [Appwrite](https://github.com/appwrite), [Mercedes-Benz Group](https://github.com/mercedes-benz), [embark-studios](https://github.com/embark-studios) and many other users and organisations via [GitHub Sponsors](https://github.com/sponsors/Homebrew).
 
 [![GitHub](https://github.com/github.png?size=64)](https://github.com/github)