diff --git a/wp-admin/update-core.php b/wp-admin/update-core.php
index a8eb7f5..e6b9b0c 100644
--- a/wp-admin/update-core.php
+++ b/wp-admin/update-core.php
@@ -162,7 +162,7 @@ function core_upgrade_preamble() {
 		}
 		echo '</h3>';
 	} else {
-		echo '<div class="updated inline"><p>';
+		echo '<div class="notice notice-warning"><p>';
 		_e('<strong>Important:</strong> before updating, please <a href="https://codex.wordpress.org/WordPress_Backups">back up your database and files</a>. For help with updates, visit the <a href="https://codex.wordpress.org/Updating_WordPress">Updating WordPress</a> Codex page.');
 		echo '</p></div>';