diff --git a/core/assets/scaffold/files/example.settings.local.php b/core/assets/scaffold/files/example.settings.local.php
index 73671ab164..1397e9ddf4 100644
--- a/core/assets/scaffold/files/example.settings.local.php
+++ b/core/assets/scaffold/files/example.settings.local.php
@@ -26,9 +26,9 @@
  * @see http://php.net/assert
  * @see https://www.drupal.org/node/2492225
  *
- * If you are using PHP 7.0 it is strongly recommended that you set
- * zend.assertions=1 in the PHP.ini file (It cannot be changed from .htaccess
- * or runtime) on development machines and to 0 in production.
+ * It is strongly recommended that you set zend.assertions=1 in the PHP.ini file
+ * (It cannot be changed from .htaccess or runtime) on development machines and
+ * to 0 or -1 in production.
  *
  * @see https://wiki.php.net/rfc/expectations
  */
diff --git a/core/lib/Drupal/Core/Database/Install/Tasks.php b/core/lib/Drupal/Core/Database/Install/Tasks.php
index b7fceace11..abb90e500b 100644
--- a/core/lib/Drupal/Core/Database/Install/Tasks.php
+++ b/core/lib/Drupal/Core/Database/Install/Tasks.php
@@ -279,8 +279,6 @@ public function getFormOptions(array $database) {
     ];
 
     global $install_state;
-    // @todo https://www.drupal.org/project/drupal/issues/3110839 remove PHP 7.4
-    //   work around and add a better message for the migrate UI.
     $profile = $install_state['parameters']['profile'] ?? NULL;
     $db_prefix = ($profile == 'standard') ? 'drupal_' : $profile . '_';
     $form['advanced_options']['prefix'] = [
diff --git a/core/lib/Drupal/Core/Routing/Router.php b/core/lib/Drupal/Core/Routing/Router.php
index 87324a68a5..23d6ebb66f 100644
--- a/core/lib/Drupal/Core/Routing/Router.php
+++ b/core/lib/Drupal/Core/Routing/Router.php
@@ -107,19 +107,7 @@ public function match($pathinfo): array {
    * {@inheritdoc}
    */
   public function matchRequest(Request $request): array {
-    try {
-      $collection = $this->getInitialRouteCollection($request);
-    }
-    // PHP 7.4 introduces changes to its serialization format, which mean that
-    // older versions of PHP are unable to unserialize data that is serialized
-    // in PHP 7.4. If the site's version of PHP has been downgraded, then
-    // attempting to unserialize routes from the database will fail, and so the
-    // router needs to be rebuilt on the current PHP version.
-    // See https://www.php.net/manual/en/migration74.incompatible.php.
-    catch (\TypeError $e) {
-      \Drupal::service('router.builder')->rebuild();
-      $collection = $this->getInitialRouteCollection($request);
-    }
+    $collection = $this->getInitialRouteCollection($request);
     if ($collection->count() === 0) {
       throw new ResourceNotFoundException(sprintf('No routes found for "%s".', $this->currentPath->getPath()));
     }
diff --git a/core/tests/Drupal/Tests/BrowserHtmlDebugTrait.php b/core/tests/Drupal/Tests/BrowserHtmlDebugTrait.php
index 4288598a59..e0b85ef546 100644
--- a/core/tests/Drupal/Tests/BrowserHtmlDebugTrait.php
+++ b/core/tests/Drupal/Tests/BrowserHtmlDebugTrait.php
@@ -180,7 +180,7 @@ protected function getResponseLogHandler() {
               $html_output .= '<hr />' . $request->getMethod() . ' request to: ' . $request->getUri();
 
               // Get the response body as a string. Any errors are silenced as
-              // tests should not fail if there is a problem. On PHP 7.4
+              // tests should not fail if there is a problem.
               // \Drupal\Tests\migrate\Functional\process\DownloadFunctionalTest
               // fails without the usage of a silence operator.
               $body = @(string) $response->getBody();
diff --git a/core/tests/README.md b/core/tests/README.md
index f88289f48c..36655e3f12 100644
--- a/core/tests/README.md
+++ b/core/tests/README.md
@@ -42,7 +42,6 @@ to install the following additional software:
 * Google Chrome or Chromium browser
 * chromedriver (tested with version 2.45) -- see
   https://sites.google.com/chromium.org/driver/
-* PHP 7.1 or higher
 
 ## Running tests
 
diff --git a/sites/example.settings.local.php b/sites/example.settings.local.php
index 73671ab164..1397e9ddf4 100644
--- a/sites/example.settings.local.php
+++ b/sites/example.settings.local.php
@@ -26,9 +26,9 @@
  * @see http://php.net/assert
  * @see https://www.drupal.org/node/2492225
  *
- * If you are using PHP 7.0 it is strongly recommended that you set
- * zend.assertions=1 in the PHP.ini file (It cannot be changed from .htaccess
- * or runtime) on development machines and to 0 in production.
+ * It is strongly recommended that you set zend.assertions=1 in the PHP.ini file
+ * (It cannot be changed from .htaccess or runtime) on development machines and
+ * to 0 or -1 in production.
  *
  * @see https://wiki.php.net/rfc/expectations
  */