diff --git a/core/includes/errors.inc b/core/includes/errors.inc
index ae29202ba90cbcdd0d9ed2584033a6baa860ed6d..2015dbd3e8998684a6109793d21bff87a3458292 100644
--- a/core/includes/errors.inc
+++ b/core/includes/errors.inc
@@ -34,7 +34,6 @@ function drupal_error_levels() {
     E_USER_ERROR => ['User error', RfcLogLevel::ERROR],
     E_USER_WARNING => ['User warning', RfcLogLevel::WARNING],
     E_USER_NOTICE => ['User notice', RfcLogLevel::NOTICE],
-    E_STRICT => ['Strict warning', RfcLogLevel::DEBUG],
     E_RECOVERABLE_ERROR => ['Recoverable fatal error', RfcLogLevel::ERROR],
     E_DEPRECATED => ['Deprecated function', RfcLogLevel::DEBUG],
     E_USER_DEPRECATED => ['User deprecated function', RfcLogLevel::DEBUG],
diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index ae5a99cdb1b0f72d87b56bae42a011e65faf46ec..2d9b63dfd7905ee8c499ef5e10b3f0b2c236c141 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -983,8 +983,7 @@ public static function bootEnvironment($app_root = NULL) {
       $app_root = static::guessApplicationRoot();
     }
 
-    // Enforce E_STRICT, but allow users to set levels not part of E_STRICT.
-    error_reporting(E_STRICT | E_ALL);
+    error_reporting(E_ALL);
 
     // Override PHP settings required for Drupal to work properly.
     // sites/default/default.settings.php contains more runtime settings.