diff --git a/src/CacheMiddleware.php b/src/CacheMiddleware.php
index cc961c97..4776e90f 100644
--- a/src/CacheMiddleware.php
+++ b/src/CacheMiddleware.php
@@ -218,7 +218,7 @@ function (ResponseInterface $response) use ($request, $cacheEntry) {
                         $response = $response->withHeader(self::HEADER_CACHE_INFO, self::HEADER_CACHE_MISS);
                     }
 
-                    return self::addToCache($this->cacheStorage, $request, $response, $update);
+                    return static::addToCache($this->cacheStorage, $request, $response, $update);
                 },
                 function ($reason) use ($cacheEntry) {
                     if ($reason instanceof TransferException) {
@@ -300,7 +300,7 @@ protected function addReValidationRequest(
                         $update = true;
                     }
 
-                    self::addToCache($cacheStorage, $request, $response, $update);
+                    static::addToCache($cacheStorage, $request, $response, $update);
                 });
 
             return true;