diff -u b/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
--- b/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -28,11 +28,10 @@
  * - If a site managed to bypass all of the above, then an error is shown in
  *   the status report and various fatal errors occur on various pages.
  *
- * @see install.php
- *
  * @deprecated in Drupal 8.7.x, will be removed before Drupal 9.0.0. Use
  *   \Drupal\Core\Requirements::MINIMUM_PHP instead.
  *
+ * @see install.php
  * @see https://www.drupal.org/node/2909361
  */
 const DRUPAL_MINIMUM_PHP = Requirements::MINIMUM_PHP;
@@ -46,10 +45,12 @@
  *   that Drupal no longer supports that PHP version.
  * - An error is shown in the status report that the PHP version is too old.
  *
- * @todo Move this to an appropriate autoloadable class. See
- *   https://www.drupal.org/project/drupal/issues/2908079
+ * @deprecated in Drupal 8.8.x, will be removed before Drupal 9.0.0. Use
+ *   \Drupal\Core\Requirements::MINIMUM_SUPPORTED_PHP instead.
+ *
+ * @see https://www.drupal.org/node/2909361
  */
-const DRUPAL_MINIMUM_SUPPORTED_PHP = '7.0.8';
+const DRUPAL_MINIMUM_SUPPORTED_PHP = Requirements::MINIMUM_SUPPORTED_PHP;
 
 /**
  * Minimum recommended version of PHP.
@@ -59,7 +60,7 @@
  * that have reached their EOL or will in the near future.
  *
  * @deprecated in Drupal 8.7.x, will be removed before Drupal 9.0.0. Use
- *   \Drupal\Core\Requirements::MINIMUM_PHP instead.
+ *   \Drupal\Core\Requirements::RECOMMENDED_PHP instead.
  *
  * @see https://www.drupal.org/node/2909361
  */
diff -u b/core/install.php b/core/install.php
--- b/core/install.php
+++ b/core/install.php
@@ -6,7 +6,6 @@
  */
 
 use Drupal\Component\Utility\OpCodeCache;
-use Drupal\Core\Requirements;
 
 // Change the directory to the Drupal root.
 chdir('..');
@@ -22,14 +21,6 @@
  */
 define('MAINTENANCE_MODE', 'install');
 
-// Checking minimum PHP version to avoid fatal errors. The minimum version is
-// specified in the Drupal\Core\Requirements class.
-require_once __DIR__ . '/lib/Drupal/Core/Requirements.php';
-if (version_compare(PHP_VERSION, Requirements::MINIMUM_PHP) < 0) {
-  print 'Your PHP installation is too old. Drupal requires at least PHP ' . Requirements::MINIMUM_PHP . '. See the <a href="https://www.drupal.org/requirements">system requirements</a> page for more information.';
-  exit;
-}
-
 // Initialize the autoloader.
 $class_loader = require_once $root_path . '/autoload.php';
 
diff -u b/core/lib/Drupal/Core/Requirements.php b/core/lib/Drupal/Core/Requirements.php
--- b/core/lib/Drupal/Core/Requirements.php
+++ b/core/lib/Drupal/Core/Requirements.php
@@ -32,2 +32,13 @@
 
+  /**
+   * Minimum supported version of PHP.
+   *
+   * Below this version:
+   * - New sites cannot be installed, except from within tests.
+   * - Updates from previous Drupal versions can be run, but users are warned
+   *   that Drupal no longer supports that PHP version.
+   * - An error is shown in the status report that the PHP version is too old.
+   */
+  const MINIMUM_SUPPORTED_PHP = '7.0.8';
+
 }
diff -u b/core/modules/system/system.install b/core/modules/system/system.install
--- b/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -187,10 +187,10 @@
   }
 
   // Check if the PHP version is below what Drupal supports.
-  if (version_compare($phpversion, DRUPAL_MINIMUM_SUPPORTED_PHP) < 0) {
+  if (version_compare($phpversion, Requirements::MINIMUM_SUPPORTED_PHP) < 0) {
     $requirements['php']['description'] = t('Your PHP installation is too old. Drupal requires at least PHP %version. It is recommended to upgrade to PHP version %recommended or higher for the best ongoing support. See <a href="http://php.net/supported-versions.php">PHP\'s version support documentation</a> and the <a href=":php_requirements">Drupal 8 PHP requirements handbook page</a> for more information.',
       [
-        '%version' => DRUPAL_MINIMUM_SUPPORTED_PHP,
+        '%version' => Requirements::MINIMUM_SUPPORTED_PHP,
         '%recommended' => Requirements::RECOMMENDED_PHP,
         ':php_requirements' => 'https://www.drupal.org/docs/8/system-requirements/php',
       ]
only in patch2:
unchanged:
--- a/core/composer.json
+++ b/core/composer.json
@@ -225,7 +225,8 @@
             "lib/Drupal/Core/DrupalKernel.php",
             "lib/Drupal/Core/DrupalKernelInterface.php",
             "lib/Drupal/Core/Site/Settings.php"
-        ]
+        ],
+        "files": ["lib/autoloader.php"]
     },
     "config": {
         "preferred-install": "dist",
only in patch2:
unchanged:
--- /dev/null
+++ b/core/lib/autoloader.php
@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains on autoload include event related functionality.
+ */
+
+use Drupal\Core\Requirements;
+
+// Checking minimum PHP version to avoid fatal errors.
+if (version_compare(PHP_VERSION, Requirements::MINIMUM_PHP) < 0) {
+  print 'Your PHP installation is too old. Drupal requires at least PHP ' . Requirements::MINIMUM_PHP . '. See the <a href="https://www.drupal.org/requirements">system requirements</a> page for more information.';
+  exit;
+}