diff --git a/core.api.php b/core.api.php
index 8db17509676..a7662f8362a 100644
--- a/core.api.php
+++ b/core.api.php
@@ -188,7 +188,7 @@
  * // Find out when cron was last run; the key is 'system.cron_last'.
  * $time = $state->get('system.cron_last');
  * // Set the cron run time to the current request time.
- * $state->set('system.cron_last', REQUEST_TIME);
+ * $state->set('system.cron_last', \Drupal::time()->getRequestTime());
  * @endcode
  *
  * For more on the State API, see https://www.drupal.org/developing/api/8/state
@@ -1919,10 +1919,11 @@ function hook_cron() {
   // Short-running operation example, not using a queue:
   // Delete all expired records since the last cron run.
   $expires = \Drupal::state()->get('mymodule.last_check', 0);
+  $request_time = \Drupal::time()->getRequestTime();
   \Drupal::database()->delete('mymodule_table')
     ->condition('expires', $expires, '>=')
     ->execute();
-  \Drupal::state()->set('mymodule.last_check', REQUEST_TIME);
+  \Drupal::state()->set('mymodule.last_check', $request_time);
 
   // Long-running operation example, leveraging a queue:
   // Queue news feeds for updates once their refresh interval has elapsed.
@@ -1931,13 +1932,13 @@ function hook_cron() {
   foreach (Feed::loadMultiple($ids) as $feed) {
     if ($queue->createItem($feed)) {
       // Add timestamp to avoid queueing item more than once.
-      $feed->setQueuedTime(REQUEST_TIME);
+      $feed->setQueuedTime($request_time);
       $feed->save();
     }
   }
   $ids = \Drupal::entityQuery('mymodule_feed')
     ->accessCheck(FALSE)
-    ->condition('queued', REQUEST_TIME - (3600 * 6), '<')
+    ->condition('queued', $request_time - (3600 * 6), '<')
     ->execute();
   if ($ids) {
     $feeds = Feed::loadMultiple($ids);
diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index 8e3b73ad13e..03af0c0a866 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -252,7 +252,7 @@ function drupal_valid_test_ua($new_prefix = NULL) {
     }
     // The file properties add more entropy not easily accessible to others.
     $key = $private_key . filectime(__FILE__) . fileinode(__FILE__);
-    $time_diff = REQUEST_TIME - $time;
+    $time_diff = time() - $time;
     $test_hmac = Crypt::hmacBase64($check_string, $key);
     // Since we are making a local request a 600 second time window is allowed,
     // and the HMAC must match.
diff --git a/includes/common.inc b/includes/common.inc
index 97b36a3d15a..dfcf090a52f 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -532,7 +532,7 @@ function drupal_flush_all_caches($kernel = NULL) {
  */
 function _drupal_flush_css_js() {
   // The timestamp is converted to base 36 in order to make it more compact.
-  Drupal::state()->set('system.css_js_query_string', base_convert(REQUEST_TIME, 10, 36));
+  Drupal::state()->set('system.css_js_query_string', base_convert(\Drupal::time()->getRequestTime(), 10, 36));
 }
 
 /**
diff --git a/includes/install.core.inc b/includes/install.core.inc
index 524c279fa78..d3af268cc69 100644
--- a/includes/install.core.inc
+++ b/includes/install.core.inc
@@ -1054,11 +1054,12 @@ function install_display_output($output, $install_state) {
 
   $bare_html_page_renderer = \Drupal::service('bare_html_page_renderer');
   $response = $bare_html_page_renderer->renderBarePage($output, $output['#title'], 'install_page', $regions);
+  $request_time = \Drupal::time()->getRequestTime();
   $default_headers = [
     'Expires' => 'Sun, 19 Nov 1978 05:00:00 GMT',
-    'Last-Modified' => gmdate(DATE_RFC1123, REQUEST_TIME),
+    'Last-Modified' => gmdate(DATE_RFC1123, $request_time),
     'Cache-Control' => 'no-cache, must-revalidate',
-    'ETag' => '"' . REQUEST_TIME . '"',
+    'ETag' => '"' . $request_time . '"',
   ];
   $response->headers->add($default_headers);
   $response->send();
@@ -1881,7 +1882,7 @@ function install_finished(&$install_state) {
   \Drupal::messenger()->addStatus($success_message);
 
   // Record when this install ran.
-  \Drupal::state()->set('install_time', $_SERVER['REQUEST_TIME']);
+  \Drupal::state()->set('install_time', \Drupal::time()->getRequestTime());
 }
 
 /**
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 883c95f1d7c..e7bcbbb2055 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -1,25 +1,10 @@
 parameters:
 	ignoreErrors:
-		-
-			message: "#^Call to deprecated constant REQUEST_TIME\\: Deprecated in drupal\\:8\\.3\\.0 and is removed from drupal\\:10\\.0\\.0\\. Use \\\\Drupal\\:\\:time\\(\\)\\-\\>getRequestTime\\(\\); $#"
-			count: 1
-			path: includes/bootstrap.inc
-
-		-
-			message: "#^Call to deprecated constant REQUEST_TIME\\: Deprecated in drupal\\:8\\.3\\.0 and is removed from drupal\\:10\\.0\\.0\\. Use \\\\Drupal\\:\\:time\\(\\)\\-\\>getRequestTime\\(\\); $#"
-			count: 1
-			path: includes/common.inc
-
 		-
 			message: "#^Function format_size\\(\\) should return Drupal\\\\Core\\\\StringTranslation\\\\TranslatableMarkup but return statement is missing\\.$#"
 			count: 1
 			path: includes/common.inc
 
-		-
-			message: "#^Call to deprecated constant REQUEST_TIME\\: Deprecated in drupal\\:8\\.3\\.0 and is removed from drupal\\:10\\.0\\.0\\. Use \\\\Drupal\\:\\:time\\(\\)\\-\\>getRequestTime\\(\\); $#"
-			count: 2
-			path: includes/install.core.inc
-
 		-
 			message: "#^Function install_config_download_translations\\(\\) should return string but return statement is missing\\.$#"
 			count: 1
@@ -2618,7 +2603,6 @@ parameters:
 			count: 1
 			path: modules/system/tests/modules/service_provider_test/src/TestFileUsage.php
 
-
 		-
 			message: "#^Access to an undefined property Drupal\\\\Tests\\\\system\\\\Functional\\\\Entity\\\\EntityListBuilderTest\\:\\:\\$webUser\\.$#"
 			count: 1
@@ -3524,7 +3508,6 @@ parameters:
 			count: 1
 			path: modules/workspaces/src/WorkspacePublisher.php
 
-
 		-
 			message: "#^Access to an undefined property Drupal\\\\Tests\\\\workspaces\\\\Kernel\\\\EntityReferenceSupportedNewEntitiesConstraintValidatorTest\\:\\:\\$entityTypeManager\\.$#"
 			count: 2
@@ -3540,11 +3523,6 @@ parameters:
 			count: 5
 			path: profiles/demo_umami/modules/demo_umami_content/src/InstallHelper.php
 
-		-
-			message: "#^Call to deprecated constant REQUEST_TIME\\: Deprecated in drupal\\:8\\.3\\.0 and is removed from drupal\\:10\\.0\\.0\\. Use \\\\Drupal\\:\\:time\\(\\)\\-\\>getRequestTime\\(\\); $#"
-			count: 1
-			path: rebuild.php
-
 		-
 			message: "#^Access to an undefined property Drupal\\\\BuildTests\\\\Framework\\\\BuildTestBase\\:\\:\\$phpFinder\\.$#"
 			count: 1
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 543c5d50ef8..41bedcd7d32 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -18,6 +18,9 @@ parameters:
     - ../*/node_modules/*
     - */tests/fixtures/*.php
     - */tests/fixtures/*.php.gz
+    # Skip Drupal 6 & 7 code.
+    - core/scripts/generate-d6-content.sh
+    - core/scripts/generate-d7-content.sh
     # Skip data files.
     - lib/Drupal/Component/Transliteration/data/*.php
     # Below extends on purpose a non existing class for testing.
diff --git a/rebuild.php b/rebuild.php
index 0c4d0d91c08..4a6bc87a6d5 100644
--- a/rebuild.php
+++ b/rebuild.php
@@ -38,7 +38,7 @@
 
 if (Settings::get('rebuild_access', FALSE) ||
   ($request->query->get('token') && $request->query->get('timestamp') &&
-    ((REQUEST_TIME - $request->query->get('timestamp')) < 300) &&
+    (($request->server->getInt('REQUEST_TIME') - $request->query->get('timestamp')) < 300) &&
     hash_equals(Crypt::hmacBase64($request->query->get('timestamp'), Settings::get('hash_salt')), $request->query->get('token'))
   )) {
   // Clear user cache for all major platforms.
diff --git a/scripts/generate-d7-content.sh b/scripts/generate-d7-content.sh
index 8b591f42b03..c7547b08424 100644
--- a/scripts/generate-d7-content.sh
+++ b/scripts/generate-d7-content.sh
@@ -237,7 +237,7 @@ for ($i = 0; $i < 12; $i++) {
   $node->status = intval($i / 2) % 2;
   $node->revision = 1;
   $node->promote = $i % 2;
-  $node->created = REQUEST_TIME + $i * 43200;
+  $node->created = $_SERVER['REQUEST_TIME'] + $i * 43200;
   $node->runtime = 0;
   $node->active = 1;
   $node->log = "added $i poll";