diff --git a/readme.txt b/readme.txt
index ae7dd9a..d292c93 100644
--- a/readme.txt
+++ b/readme.txt
@@ -3,12 +3,12 @@ Contributors: cadeyrn
 Donate link: https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=XU3DG7LLA76WC
 Tags: cache, page cache, full page cache, nginx, memcached, apc, speed
 Requires at least: 3.0
-Tested up to: 3.9
-Stable tag: 1.4.0
+Tested up to: 3.9.1
+Stable tag: 1.5.0
 License: GPLv3
 License URI: http://www.gnu.org/licenses/gpl-3.0.html
 
-The fastest way to cache: full page in memory cache for WordPress!
+The fastest way to cache: use the memory!
 
 == Description ==
 WP-FFPC ( WordPress Fast Full Page Cache ) is a cache plugin for [WordPress](http://wordpress.org/ "WordPress"). It works with any webserver, including apache2, lighttpd, nginx.
@@ -16,12 +16,14 @@ It can be configured to join forces with [NGiNX](http://NGiNX.org "NGiNX")'s bui
 
 = Features: =
 * Wordpress Network support
-  * fully supported domain/subdomain Networks
+  * fully supported domain/subdomain based WordPress Networks on per site setup as well
   * will work in Network Enabled mode only for subdirectory based Multisites ( no per site setting possibility )
 * supports variable backends
-  * memcached with PHP Memcached
-  * memcached with PHP Memcache
-  * APC
+  * memcached with [PHP Memcached](http://php.net/manual/en/book.memcached.php "Memcached")
+  * memcached with [PHP Memcache](http://php.net/manual/en/book.memcache.php "Memcache")
+  * [APC](http://php.net/manual/en/book.apc.php "APC")
+  * [APCu](http://pecl.php.net/package/APCu "APC User Cache")
+  * [Xcache](http://xcache.lighttpd.net/ "Xcache") - not stable yet, volunteer testers required!
 * cache exclude possibilities ( home, feeds, archieves, pages, singles )
 * (optional) cache for logged-in users
 * 404 caching
@@ -33,7 +35,7 @@ It can be configured to join forces with [NGiNX](http://NGiNX.org "NGiNX")'s bui
 * multiple memcached upstream support
 * precache ( manually or by timed by wp-cron )
 
-Many thanks for contributors, supporters, testers & bug reporters:
+Many thanks for donations, contributors, supporters, testers & bug reporters:
 
 * [Harold Kyle](https://github.com/haroldkyle "Harold Kyle")
 * [Eric Gilette](http://www.ericgillette.com/ "Eric Gilette")
@@ -69,10 +71,11 @@ From version 1.0, the plugin supports subdomain based WordPress Network with pos
 
 and **at least one** of the following for storage backend:
 
-* PHP APC
-* PHP Memcached > 0.1.0
-* PHP Memcache > 2.1.0
-* Xcache
+* memcached with [PHP Memcached](http://php.net/manual/en/book.memcached.php "Memcached") > 0.1.0
+* memcached with [PHP Memcache](http://php.net/manual/en/book.memcache.php "Memcache") > 2.1.0
+* [APC](http://php.net/manual/en/book.apc.php "APC")
+* [APCu](http://pecl.php.net/package/APCu "APC User Cache")
+* [Xcache](http://xcache.lighttpd.net/ "Xcache")
 
 = How logging works in the plugin? =
 Log levels by default ( if logging enabled ) includes warning and error level standard PHP messages.
@@ -95,12 +98,22 @@ Please post feature requests to [WP-FFPC feature request topic](http://wordpress
 
 == Changelog ==
 
+= 1.5.0 =
+*2014-05-30*
+
+What's new:
+
+* APCu backend added ( APCu is a stripped version of APC with only user object cache functionality what can be used with PHP 5.4 & 5.5 besides [Opcache](http://php.net/manual/en/book.opcache.php "PHP Opcache") )
+
 = 1.4.0 =
 *2014-05-12*
 
-What's changed:
+What's new:
+
+* Xcache backend added ( theoretical, partially tested, volunteer testers required )
+
+What's fixed:
 
-* Xcache backend added ( alpha version, still under heavy testing )
 * invalidation for comment actions added
 
 = 1.3.3 =
diff --git a/wp-ffpc-backend.php b/wp-ffpc-backend.php
index f64bdaa..c30f401 100644
--- a/wp-ffpc-backend.php
+++ b/wp-ffpc-backend.php
@@ -166,7 +166,7 @@ if (!class_exists('WP_FFPC_Backend')) {
 			$this->log ( sprintf( __translate__( 'set %s expiration time: %s', $this->plugin_constant ),  $key, $this->options['expire'] ) );
 
 			/* proxy to internal function */
-			$internal = $this->options['cache_type'] . '_set';
+			$internal = $this->proxy( 'set' );
 			$result = $this->$internal( $key, $data );
 
 			/* check result validity */
@@ -448,13 +448,13 @@ if (!class_exists('WP_FFPC_Backend')) {
 		 */
 		private function apc_init () {
 			/* verify apc functions exist, apc extension is loaded */
-			if ( ! function_exists( 'apc_sma_info' ) ) {
+			if ( ! function_exists( 'apc_cache_info' ) ) {
 				$this->log (  __translate__('APC extension missing', $this->plugin_constant ) );
 				return false;
 			}
 
 			/* verify apc is working */
-			if ( apc_sma_info() ) {
+			if ( apc_cache_info("user",true) ) {
 				$this->log (  __translate__('backend OK', $this->plugin_constant ) );
 				$this->alive = true;
 			}
@@ -527,6 +527,92 @@ if (!class_exists('WP_FFPC_Backend')) {
 			}
 		}
 
+		/*********************** END APC FUNCTIONS ***********************/
+		/*********************** APCu FUNCTIONS ***********************/
+		/**
+		 * init apcu backend: test APCu availability and set alive status
+		 */
+		private function apcu_init () {
+			/* verify apcu functions exist, apcu extension is loaded */
+			if ( ! function_exists( 'apcu_cache_info' ) ) {
+				$this->log (  __translate__('APCu extension missing', $this->plugin_constant ) );
+				return false;
+			}
+
+			/* verify apcu is working */
+			if ( apcu_cache_info("user",true) ) {
+				$this->log (  __translate__('backend OK', $this->plugin_constant ) );
+				$this->alive = true;
+			}
+		}
+
+		/**
+		 * health checker for APC
+		 *
+		 * @return boolean Aliveness status
+		 *
+		 */
+		private function apcu_status () {
+			$this->status = true;
+			return $this->alive;
+		}
+
+		/**
+		 * get function for APC backend
+		 *
+		 * @param string $key Key to get values for
+		 *
+		 * @return mixed Fetched data based on key
+		 *
+		*/
+		private function apcu_get ( &$key ) {
+			return apcu_fetch( $key );
+		}
+
+		/**
+		 * Set function for APC backend
+		 *
+		 * @param string $key Key to set with
+		 * @param mixed $data Data to set
+		 *
+		 * @return boolean APC store outcome
+		 */
+		private function apcu_set (  &$key, &$data ) {
+			return apcu_store( $key , $data , $this->options['expire'] );
+		}
+
+
+		/**
+		 * Flushes APC user entry storage
+		 *
+		 * @return boolean APC flush outcome status
+		 *
+		*/
+		private function apcu_flush ( ) {
+			return apcu_clear_cache();
+		}
+
+		/**
+		 * Removes entry from APC or flushes APC user entry storage
+		 *
+		 * @param mixed $keys Keys to clear, string or array
+		*/
+		private function apcu_clear ( &$keys ) {
+			/* make an array if only one string is present, easier processing */
+			if ( !is_array ( $keys ) )
+				$keys = array ( $keys => true );
+
+			foreach ( $keys as $key => $dummy ) {
+				if ( ! apcu_delete ( $key ) ) {
+					$this->log ( sprintf( __translate__( 'Failed to delete APC entry: %s', $this->plugin_constant ),  $key ), LOG_ERR );
+					//throw new Exception ( __translate__('Deleting APC entry failed with key ', $this->plugin_constant ) . $key );
+				}
+				else {
+					$this->log ( sprintf( __translate__( 'APC entry delete: %s', $this->plugin_constant ),  $key ) );
+				}
+			}
+		}
+
 		/*********************** END APC FUNCTIONS ***********************/
 
 		/*********************** XCACHE FUNCTIONS ***********************/
diff --git a/wp-ffpc-class.php b/wp-ffpc-class.php
index 52867c1..83c1310 100644
--- a/wp-ffpc-class.php
+++ b/wp-ffpc-class.php
@@ -115,13 +115,15 @@ if ( ! class_exists( 'WP_FFPC' ) ) {
 			/* cache type possible values array */
 			$this->select_cache_type = array (
 				'apc' => __( 'APC' , $this->plugin_constant ),
+				'apcu' => __( 'APCu' , $this->plugin_constant ),
 				'xcache' => __( 'XCache' , $this->plugin_constant ),
 				'memcache' => __( 'PHP Memcache' , $this->plugin_constant ),
 				'memcached' => __( 'PHP Memcached' , $this->plugin_constant ),
 			);
 			/* check for required functions / classes for the cache types */
 			$this->valid_cache_type = array (
-				'apc' => function_exists( 'apc_sma_info' ) ? true : false,
+				'apc' => function_exists( 'apc_cache_info' ) ? true : false,
+				'apcu' => function_exists( 'apcu_cache_info' ) ? true : false,
 				'xcache' => function_exists( 'xcache_info' ) ? true : false,
 				'memcache' => class_exists ( 'Memcache') ? true : false,
 				'memcached' => class_exists ( 'Memcached') ? true : false,
diff --git a/wp-ffpc.php b/wp-ffpc.php
index 7361e1c..97d793d 100644
--- a/wp-ffpc.php
+++ b/wp-ffpc.php
@@ -3,7 +3,7 @@
 Plugin Name: WP-FFPC
 Plugin URI: http://petermolnar.eu/wordpress/wp-ffpc
 Description: WordPress cache plugin for memcached & nginx - unbeatable speed
-Version: 1.4.0
+Version: 1.5.0
 Author: Peter Molnar <hello@petermolnar.eu>
 Author URI: http://petermolnar.eu/
 License: GPLv3