app/Config/Feature.php

+<?php
+
+declare(strict_types=1);
+
+namespace Config;
+
+use CodeIgniter\Config\BaseConfig;
+
+/**
+ * Enable/disable backward compatibility breaking features.
+ */
+class Feature extends BaseConfig
+{
+    /**
+     * Use improved new auto routing instead of the legacy version.
+     */
+    public bool $autoRoutesImproved = true;
+
+    /**
+     * Use filter execution order in 4.4 or before.
+     */
+    public bool $oldFilterOrder = false;
+
+    /**
+     * The behavior of `limit(0)` in Query Builder.
+     *
+     * If true, `limit(0)` returns all records. (the behavior of 4.4.x or before in version 4.x.)
+     * If false, `limit(0)` returns no records. (the behavior of 3.1.9 or later in version 3.x.)
+     */
+    public bool $limitZeroAsAll = true;
+
+    /**
+     * Use strict location negotiation.
+     *
+     * By default, the locale is selected based on a loose comparison of the language code (ISO 639-1)
+     * Enabling strict comparison will also consider the region code (ISO 3166-1 alpha-2).
+     */
+    public bool $strictLocaleNegotiation = false;
+}

app/Config/ForeignCharacters.php

 <?php
 
+declare(strict_types=1);
+
 namespace Config;
 
 use CodeIgniter\Config\ForeignCharacters as BaseForeignCharacters;
 
+/**
+ * @immutable
+ */
 class ForeignCharacters extends BaseForeignCharacters
 {
 }