diff --git a/lib/PHPPdf/Cache/CacheImpl.php b/lib/PHPPdf/Cache/CacheImpl.php
index a85571b0..4ed4d68f 100644
--- a/lib/PHPPdf/Cache/CacheImpl.php
+++ b/lib/PHPPdf/Cache/CacheImpl.php
@@ -21,6 +21,7 @@ class CacheImpl implements Cache
 {
     const ENGINE_FILE = 'File';
     const ENGINE_APC = 'Apc';
+    const ENGINE_APCU = 'Apcu';
     const ENGINE_MEMCACHED = 'Memcached';
     const ENGINE_FILESYSTEM = 'Filesystem';
     
@@ -150,4 +151,4 @@ public function remove($id)
             $this->wrapLowLevelException($e, __METHOD__);
         }
     }
-}
\ No newline at end of file
+}