diff --git a/src/Core/Cache/AbstractCacheDriver.php b/src/Core/Cache/AbstractCacheDriver.php
index 6974dff1b..ac33467b9 100644
--- a/src/Core/Cache/AbstractCacheDriver.php
+++ b/src/Core/Cache/AbstractCacheDriver.php
@@ -11,7 +11,7 @@ use Friendica\BaseObject;
  *
  * @package Friendica\Core\Cache
  */
-abstract class AbstractCacheDriver extends BaseObject implements IMemoryCacheDriver
+abstract class AbstractCacheDriver extends BaseObject
 {
 	/**
 	 * @param string $key	The original key
diff --git a/src/Core/Cache/ArrayCache.php b/src/Core/Cache/ArrayCache.php
index 714021c72..ec9f3a257 100644
--- a/src/Core/Cache/ArrayCache.php
+++ b/src/Core/Cache/ArrayCache.php
@@ -12,7 +12,7 @@ use Friendica\Core\Cache;
  *
  * @package Friendica\Core\Cache
  */
-class ArrayCache extends AbstractCacheDriver
+class ArrayCache extends AbstractCacheDriver implements IMemoryCacheDriver
 {
 	use TraitCompareDelete;
 
diff --git a/src/Core/Cache/DatabaseCacheDriver.php b/src/Core/Cache/DatabaseCacheDriver.php
index 0838a66c7..5c71fb196 100644
--- a/src/Core/Cache/DatabaseCacheDriver.php
+++ b/src/Core/Cache/DatabaseCacheDriver.php
@@ -12,7 +12,7 @@ use Friendica\Util\DateTimeFormat;
  *
  * @author Hypolite Petovan <mrpetovan@gmail.com>
  */
-class DatabaseCacheDriver implements ICacheDriver
+class DatabaseCacheDriver extends AbstractCacheDriver implements ICacheDriver
 {
 	public function get($key)
 	{
diff --git a/src/Core/Cache/MemcacheCacheDriver.php b/src/Core/Cache/MemcacheCacheDriver.php
index 9c16d5531..af7e5ab0e 100644
--- a/src/Core/Cache/MemcacheCacheDriver.php
+++ b/src/Core/Cache/MemcacheCacheDriver.php
@@ -9,7 +9,7 @@ use Friendica\Core\Cache;
  *
  * @author Hypolite Petovan <mrpetovan@gmail.com>
  */
-class MemcacheCacheDriver extends AbstractCacheDriver
+class MemcacheCacheDriver extends AbstractCacheDriver implements IMemoryCacheDriver
 {
 	use TraitCompareSet;
 	use TraitCompareDelete;
diff --git a/src/Core/Cache/MemcachedCacheDriver.php b/src/Core/Cache/MemcachedCacheDriver.php
index 52b6a08cf..819cf71c5 100644
--- a/src/Core/Cache/MemcachedCacheDriver.php
+++ b/src/Core/Cache/MemcachedCacheDriver.php
@@ -9,7 +9,7 @@ use Friendica\Core\Cache;
  *
  * @author Hypolite Petovan <mrpetovan@gmail.com>
  */
-class MemcachedCacheDriver extends AbstractCacheDriver
+class MemcachedCacheDriver extends AbstractCacheDriver implements IMemoryCacheDriver
 {
 	use TraitCompareSet;
 	use TraitCompareDelete;
diff --git a/src/Core/Cache/RedisCacheDriver.php b/src/Core/Cache/RedisCacheDriver.php
index 8f85e67d7..67df8e8fe 100644
--- a/src/Core/Cache/RedisCacheDriver.php
+++ b/src/Core/Cache/RedisCacheDriver.php
@@ -10,7 +10,7 @@ use Friendica\Core\Cache;
  * @author Hypolite Petovan <mrpetovan@gmail.com>
  * @author Roland Haeder <roland@mxchange.org>
  */
-class RedisCacheDriver extends AbstractCacheDriver
+class RedisCacheDriver extends AbstractCacheDriver implements IMemoryCacheDriver
 {
 	/**
 	 * @var \Redis