diff --git a/app/Config/Cache.php b/app/Config/Cache.php
index c82e3cbe646d..7dbe30f37b52 100644
--- a/app/Config/Cache.php
+++ b/app/Config/Cache.php
@@ -97,6 +97,20 @@ class Cache extends BaseConfig
      */
     public $ttl = 60;
 
+    /**
+     * --------------------------------------------------------------------------
+     * Reserved Characters
+     * --------------------------------------------------------------------------
+     *
+     * A string of reserved characters that will not be allowed in keys or tags.
+     * Strings that violate this restriction will cause handlers to throw.
+     * Default: {}()/\@:
+     * Note: The default set is required for PSR-6 compliance.
+     *
+     * @var string
+     */
+    public $reservedCharacters = '{}()/\@:';
+
     /**
      * --------------------------------------------------------------------------
      * File settings
diff --git a/system/Cache/Handlers/BaseHandler.php b/system/Cache/Handlers/BaseHandler.php
index ffd031b00134..340100e1838c 100644
--- a/system/Cache/Handlers/BaseHandler.php
+++ b/system/Cache/Handlers/BaseHandler.php
@@ -22,8 +22,10 @@
 abstract class BaseHandler implements CacheInterface
 {
     /**
-     * Reserved characters that cannot be used in a key or tag.
+     * Reserved characters that cannot be used in a key or tag. May be overridden by the config.
      * From https://github.com/symfony/cache-contracts/blob/c0446463729b89dd4fa62e9aeecc80287323615d/ItemInterface.php#L43
+     *
+     * @deprecated in favor of the Cache config
      */
     public const RESERVED_CHARACTERS = '{}()/\@:';
 
@@ -58,8 +60,10 @@ public static function validateKey($key, $prefix = ''): string
         if ($key === '') {
             throw new InvalidArgumentException('Cache key cannot be empty.');
         }
-        if (strpbrk($key, self::RESERVED_CHARACTERS) !== false) {
-            throw new InvalidArgumentException('Cache key contains reserved characters ' . self::RESERVED_CHARACTERS);
+
+        $reserved = config('Cache')->reservedCharacters ?? self::RESERVED_CHARACTERS;
+        if ($reserved && strpbrk($key, $reserved) !== false) {
+            throw new InvalidArgumentException('Cache key contains reserved characters ' . $reserved);
         }
 
         // If the key with prefix exceeds the length then return the hashed version
diff --git a/tests/system/Cache/Handlers/BaseHandlerTest.php b/tests/system/Cache/Handlers/BaseHandlerTest.php
index 133c644f1b9e..aa95da40e83e 100644
--- a/tests/system/Cache/Handlers/BaseHandlerTest.php
+++ b/tests/system/Cache/Handlers/BaseHandlerTest.php
@@ -30,6 +30,16 @@ public function invalidTypeProvider(): array
         ];
     }
 
+    public function testValidateKeyUsesConfig()
+    {
+    	config('Cache')->reservedCharacters = 'b';
+
+        $this->expectException('InvalidArgumentException');
+        $this->expectExceptionMessage('Cache key contains reserved characters b');
+
+        BaseHandler::validateKey('banana');
+    }
+
     public function testValidateKeySuccess()
     {
         $string = 'banana';
diff --git a/user_guide_src/source/changelogs/index.rst b/user_guide_src/source/changelogs/index.rst
index 038d259e4189..a997a57f0c3f 100644
--- a/user_guide_src/source/changelogs/index.rst
+++ b/user_guide_src/source/changelogs/index.rst
@@ -12,6 +12,7 @@ See all the changes.
 .. toctree::
     :titlesonly:
 
+    v4.2.0
     v4.1.4
     v4.1.3
     v4.1.2
diff --git a/user_guide_src/source/changelogs/v4.2.0.rst b/user_guide_src/source/changelogs/v4.2.0.rst
new file mode 100644
index 000000000000..c1a7d2673ab1
--- /dev/null
+++ b/user_guide_src/source/changelogs/v4.2.0.rst
@@ -0,0 +1,18 @@
+Version 4.2.0
+=============
+
+Release Date: Not released
+
+**4.2.0 release of CodeIgniter4**
+
+Enhancements:
+
+- Added Cache config for reserved characters
+
+Changes:
+
+Deprecations:
+
+- Deprecated ``CodeIgniter\\Cache\\Handlers\\BaseHandler::RESERVED_CHARACTERS`` in favor of the new config property
+
+Bugs Fixed: