diff --git a/.github/workflows/pkg-installer.yml b/.github/workflows/pkg-installer.yml
index 7733439b15..dcea80f0e4 100644
--- a/.github/workflows/pkg-installer.yml
+++ b/.github/workflows/pkg-installer.yml
@@ -32,7 +32,7 @@ jobs:
       TEMPORARY_CERTIFICATE_FILE: 'homebrew_developer_id_installer_certificate.p12'
       TEMPORARY_KEYCHAIN_FILE: 'homebrew_installer_signing.keychain-db'
       # Set to the oldest supported version of macOS
-      HOMEBREW_MACOS_OLDEST_SUPPORTED: '13.0'
+      HOMEBREW_MACOS_OLDEST_SUPPORTED: '14.0'
     permissions:
       contents: read # for code access
       attestations: write # for actions/attest-build-provenance
diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 04b76013a1..c17ed358e0 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -576,18 +576,19 @@ esac
 # - docs/Installation.md
 # - https://github.com/Homebrew/install/blob/HEAD/install.sh
 # - Library/Homebrew/os/mac.rb (latest_sdk_version)
+# - Library/Homebrew/os/mac/xcode.rb (latest_version), (minimum_version)
 # and, if needed:
 # - MacOSVersion::SYMBOLS
-HOMEBREW_MACOS_NEWEST_UNSUPPORTED="16"
+HOMEBREW_MACOS_NEWEST_UNSUPPORTED="27"
 # TODO: bump version when new macOS is released
-HOMEBREW_MACOS_NEWEST_SUPPORTED="15"
+HOMEBREW_MACOS_NEWEST_SUPPORTED="26"
 # TODO: bump version when new macOS is released and update references in:
 # - docs/Installation.md
 # - HOMEBREW_MACOS_OLDEST_SUPPORTED in .github/workflows/pkg-installer.yml
 # - `os-version min` in package/Distribution.xml
 # - https://github.com/Homebrew/install/blob/HEAD/install.sh
-HOMEBREW_MACOS_OLDEST_SUPPORTED="13"
-HOMEBREW_MACOS_OLDEST_ALLOWED="10.11"
+HOMEBREW_MACOS_OLDEST_SUPPORTED="14"
+HOMEBREW_MACOS_OLDEST_ALLOWED="10.15"
 
 if [[ -n "${HOMEBREW_MACOS}" ]]
 then
diff --git a/Library/Homebrew/os/mac.rb b/Library/Homebrew/os/mac.rb
index a0fd08b6f7..cf0058fbea 100644
--- a/Library/Homebrew/os/mac.rb
+++ b/Library/Homebrew/os/mac.rb
@@ -56,7 +56,7 @@ module OS
     def self.latest_sdk_version
       # TODO: bump version when new Xcode macOS SDK is released
       # NOTE: We only track the major version of the SDK.
-      ::Version.new("15")
+      ::Version.new("26")
     end
 
     sig { returns(String) }
diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index 4ec04e7d2d..e0edb1fe21 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -17,6 +17,7 @@ module OS
       def self.latest_version(macos: MacOS.version)
         macos = macos.strip_patch
         case macos
+        when "26" then "26.0"
         when "15" then "16.4"
         when "14" then "16.2"
         when "13" then "15.2"
@@ -43,6 +44,7 @@ module OS
       def self.minimum_version
         macos = MacOS.version
         case macos
+        when "26" then "26.0"
         when "15" then "16.0"
         when "14" then "15.0"
         when "13" then "14.1"
diff --git a/Library/Homebrew/test/cask/cask_spec.rb b/Library/Homebrew/test/cask/cask_spec.rb
index ea41dd144b..e5d2e4499c 100644
--- a/Library/Homebrew/test/cask/cask_spec.rb
+++ b/Library/Homebrew/test/cask/cask_spec.rb
@@ -364,26 +364,6 @@ RSpec.describe Cask::Cask, :cask do
             "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine/darwin/1.0.0/intel.zip",
             "version": "1.0.0",
             "sha256": "1866dfa833b123bb8fe7fa7185ebf24d28d300d0643d75798bc23730af734216"
-          },
-          "mojave": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine/darwin/1.0.0/intel.zip",
-            "version": "1.0.0",
-            "sha256": "1866dfa833b123bb8fe7fa7185ebf24d28d300d0643d75798bc23730af734216"
-          },
-          "high_sierra": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine/darwin/1.0.0/intel.zip",
-            "version": "1.0.0",
-            "sha256": "1866dfa833b123bb8fe7fa7185ebf24d28d300d0643d75798bc23730af734216"
-          },
-          "sierra": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine/darwin/1.0.0/intel.zip",
-            "version": "1.0.0",
-            "sha256": "1866dfa833b123bb8fe7fa7185ebf24d28d300d0643d75798bc23730af734216"
-          },
-          "el_capitan": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine/darwin/1.0.0/intel.zip",
-            "version": "1.0.0",
-            "sha256": "1866dfa833b123bb8fe7fa7185ebf24d28d300d0643d75798bc23730af734216"
           }
         }
       JSON
@@ -418,22 +398,6 @@ RSpec.describe Cask::Cask, :cask do
           "catalina": {
             "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel.zip",
             "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
-          },
-          "mojave": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel.zip",
-            "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
-          },
-          "high_sierra": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel.zip",
-            "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
-          },
-          "sierra": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel.zip",
-            "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
-          },
-          "el_capitan": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel.zip",
-            "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
           }
         }
       JSON
@@ -469,22 +433,6 @@ RSpec.describe Cask::Cask, :cask do
             "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel-darwin.zip",
             "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
           },
-          "mojave": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel-darwin.zip",
-            "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
-          },
-          "high_sierra": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel-darwin.zip",
-            "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
-          },
-          "sierra": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel-darwin.zip",
-            "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
-          },
-          "el_capitan": {
-            "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel-darwin.zip",
-            "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
-          },
           "x86_64_linux": {
             "url": "file://#{TEST_FIXTURE_DIR}/cask/caffeine-intel-linux.zip",
             "sha256": "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
diff --git a/Library/Homebrew/test/support/fixtures/cask/Casks/with-depends-on-everything.rb b/Library/Homebrew/test/support/fixtures/cask/Casks/with-depends-on-everything.rb
index fef3374ef7..f4e661df0f 100644
--- a/Library/Homebrew/test/support/fixtures/cask/Casks/with-depends-on-everything.rb
+++ b/Library/Homebrew/test/support/fixtures/cask/Casks/with-depends-on-everything.rb
@@ -9,7 +9,7 @@ cask "with-depends-on-everything" do
   depends_on cask: "local-caffeine"
   depends_on cask: "with-depends-on-cask"
   depends_on formula: "unar"
-  depends_on macos: ">= :el_capitan"
+  depends_on macos: ">= :catalina"
 
   app "Caffeine.app"
 end
diff --git a/Library/Homebrew/test/support/fixtures/cask/Casks/with-depends-on-macos-comparison.rb b/Library/Homebrew/test/support/fixtures/cask/Casks/with-depends-on-macos-comparison.rb
index df2688eb0b..1d1112a987 100644
--- a/Library/Homebrew/test/support/fixtures/cask/Casks/with-depends-on-macos-comparison.rb
+++ b/Library/Homebrew/test/support/fixtures/cask/Casks/with-depends-on-macos-comparison.rb
@@ -7,7 +7,7 @@ cask "with-depends-on-macos-comparison" do
   url "file://#{TEST_FIXTURE_DIR}/cask/caffeine.zip"
   homepage "https://brew.sh/with-depends-on-macos-comparison"
 
-  depends_on macos: ">= :el_capitan"
+  depends_on macos: ">= :catalina"
 
   app "Caffeine.app"
 end
diff --git a/Library/Homebrew/test/support/fixtures/cask/everything-with-variations.json b/Library/Homebrew/test/support/fixtures/cask/everything-with-variations.json
index 9f37f30fb5..72eda10923 100644
--- a/Library/Homebrew/test/support/fixtures/cask/everything-with-variations.json
+++ b/Library/Homebrew/test/support/fixtures/cask/everything-with-variations.json
@@ -82,7 +82,7 @@
     ],
     "macos": {
       ">=": [
-        "10.11"
+        "10.15"
       ]
     }
   },
diff --git a/Library/Homebrew/test/support/fixtures/cask/everything.json b/Library/Homebrew/test/support/fixtures/cask/everything.json
index a467581068..38d85c9f73 100644
--- a/Library/Homebrew/test/support/fixtures/cask/everything.json
+++ b/Library/Homebrew/test/support/fixtures/cask/everything.json
@@ -82,7 +82,7 @@
     ],
     "macos": {
       ">=": [
-        "10.11"
+        "10.15"
       ]
     }
   },
diff --git a/docs/Installation.md b/docs/Installation.md
index dbad1bebfa..92201e8b85 100644
--- a/docs/Installation.md
+++ b/docs/Installation.md
@@ -1,5 +1,5 @@
 ---
-last_review_date: "2025-04-12"
+last_review_date: "2025-09-12"
 ---
 
 # Installation
@@ -13,7 +13,7 @@ The macOS `.pkg` installer also installs Homebrew to its default prefix (`/opt/h
 ## macOS Requirements
 
 * An Apple Silicon CPU or 64-bit Intel CPU <sup>[1](#1)</sup>
-* macOS Ventura (13) (or higher) installed on officially supported hardware<sup>[2](#2)</sup>
+* macOS Sonoma (14) (or higher) installed on officially supported hardware<sup>[2](#2)</sup>
 * Command Line Tools (CLT) for Xcode (from `xcode-select --install` or
   [https://developer.apple.com/download/all/](https://developer.apple.com/download/all/)) or
   [Xcode](https://itunes.apple.com/us/app/xcode/id497799835) <sup>[3](#3)</sup>
@@ -116,7 +116,7 @@ Uninstallation is documented in the [FAQ](FAQ.md#how-do-i-uninstall-homebrew).
 
 <a data-proofer-ignore name="1"><sup>1</sup></a> For 32-bit or PPC support see [Tigerbrew](https://github.com/mistydemeo/tigerbrew).
 
-<a data-proofer-ignore name="2"><sup>2</sup></a> macOS 13 (Ventura) or higher is best and supported, 10.11 (El Capitan) – 12 (Monterey) are unsupported but may work and 10.10 (Yosemite) and older will not run Homebrew at all. For 10.4 (Tiger) – 10.6 (Snow Leopard) see [Tigerbrew](https://github.com/mistydemeo/tigerbrew). Using OpenCore Legacy Patcher is a [Tier 2](Support-Tiers.md#tier-2) or [Tier 3](Support-Tiers.md#tier-3) configuration depending on CPU generation.
+<a data-proofer-ignore name="2"><sup>2</sup></a> macOS 14 (Sonoma) or higher is best and supported, 10.15 (Catalina) – 13 (Ventura) are unsupported but may work and 10.14 (Mojave) and older will not run Homebrew at all. Using OpenCore Legacy Patcher is a [Tier 2](Support-Tiers.md#tier-2) or [Tier 3](Support-Tiers.md#tier-3) configuration depending on CPU generation.
 
 <a data-proofer-ignore name="3"><sup>3</sup></a> You may need to install Xcode, the CLT, or both depending on the formula, to install a bottle (binary package) which is the only supported configuration. Downloading Xcode may require an Apple Developer account on older versions of Mac OS X. Sign up for free at [Apple's website](https://developer.apple.com/account/).
 
diff --git a/docs/Support-Tiers.md b/docs/Support-Tiers.md
index 5732995694..3801e52c17 100644
--- a/docs/Support-Tiers.md
+++ b/docs/Support-Tiers.md
@@ -120,12 +120,7 @@ As a result, Homebrew will also drop macOS Intel x86_64 support in a future rele
 
 Here's the timescale for planned future Tier support:
 
-- Today (August 2025):
-  - Tier 1: macOS Sequoia 15, Sonoma 14, Ventura 13 on Apple Silicon and Intel x86_64
-  - Tier 2: macOS Tahoe 26
-  - Tier 3: macOS El Capitan 10.11 - Monterey 12
-  - Unsupported: OS X Yosemite 10.10 and earlier
-- September (or later) 2025:
+- Today (September 2025):
   - Tier 1: macOS Tahoe 26, Sequoia 15, Sonoma 14 on Apple Silicon and Intel x86_64
   - Tier 3: macOS Catalina 10.15 - Ventura 13
   - Unsupported: macOS Mojave 10.14 and earlier
diff --git a/package/Distribution.xml b/package/Distribution.xml
index df0b22fcce..5aafa06ae8 100644
--- a/package/Distribution.xml
+++ b/package/Distribution.xml
@@ -4,7 +4,7 @@
   <options customize="never" hostArchitectures="x86_64,arm64" rootVolumeOnly="true"/>
   <volume-check>
     <allowed-os-versions>
-        <os-version min="13.0.0"/>
+        <os-version min="14.0.0"/>
     </allowed-os-versions>
   </volume-check>
   <choices-outline>
@@ -27,7 +27,7 @@
   <license file="LICENSE.rtf"/>
   <conclusion file="CONCLUSION.rtf" />
   <allowed-os-versions>
-    <os-version min="13.0.0"/>
+    <os-version min="14.0.0"/>
   </allowed-os-versions>
 
   <script>