diff --git a/README.md b/README.md
index 02bc3a6..8237bc5 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,7 @@ version has been cherry picked over to this version.
 
 ## Installation ##
 
-1. Verify that you have PHP 5.2.4+ and a compatible APC version installed.
+1. Verify that you have PHP 5.2.4+ and a compatible APC version installed. PHP7 users will need to install the [APCu_bc][11] extension 
 2. Copy `object-cache.php` to your WordPress content directory (`wp-content/` by default).
 3. Done!
 
@@ -36,7 +36,7 @@ Maybe, but I'm not going to support them, and you shouldn't still be running the
 
 ### I share `wp-config.php` among multiple WordPress installs. How can I guarantee key uniqueness? ###
 
-Define `WP_APC_KEY_SALT` to something that is unique for each install (like an md5 of the MySQL host, database, and table prefix).
+Define `WP_CACHE_KEY_SALT` to something that is unique for each install (like an md5 of the MySQL host, database, and table prefix).
 
 ## Changelog ##
 
@@ -72,4 +72,5 @@ Define `WP_APC_KEY_SALT` to something that is unique for each install (like an m
 [7]: https://github.com/l3rady/WordPress-APC-Object-Cache/pull/1
 [8]: https://github.com/l3rady/WordPress-APC-Object-Cache/pull/7
 [9]: https://github.com/l3rady/WordPress-APC-Object-Cache/pull/9
-[10]: https://github.com/l3rady/WordPress-APC-Object-Cache/pull/10
\ No newline at end of file
+[10]: https://github.com/l3rady/WordPress-APC-Object-Cache/pull/10
+[11]: https://pecl.php.net/package/apcu_bc
diff --git a/object-cache.php b/object-cache.php
index 8707f22..9846038 100644
--- a/object-cache.php
+++ b/object-cache.php
@@ -359,12 +359,12 @@ private function __clone() {
 	private function __construct() {
 		global $blog_id;
 
-		if ( !defined( 'WP_APC_KEY_SALT' ) ) {
+		if ( !defined( 'WP_CACHE_KEY_SALT' ) ) {
 			/**
 			 * Set in config if you are using some sort of shared
 			 * config where ABSPATH is the same on all sites
 			 */
-			define( 'WP_APC_KEY_SALT', 'wp' );
+			define( 'WP_CACHE_KEY_SALT', 'wp' );
 		}
 
 		$this->abspath       = md5( ABSPATH );
@@ -385,7 +385,7 @@ private function __construct() {
 	 * @return bool False if cache key and group already exist, true on success
 	 */
 	public function add( $key, $var, $group = 'default', $ttl = 0 ) {
-		if ( wp_suspend_cache_addition() ) {
+		if ( function_exists('wp_suspend_cache_addition') && wp_suspend_cache_addition() ) {
 			return false;
 		}
 
@@ -791,7 +791,7 @@ private function _get_cache_version( $key ) {
 	 * @return string The key
 	 */
 	private function _get_cache_version_key( $type, $value ) {
-		return WP_APC_KEY_SALT . ':' . $this->abspath . ':' . $type . ':' . $value;
+		return WP_CACHE_KEY_SALT . ':' . $this->abspath . ':' . $type . ':' . $value;
 	}
 
 
@@ -969,7 +969,7 @@ private function _key( $key, $group ) {
 		$group_version = $this->_get_group_cache_version( $group );
 		$site_version  = $this->_get_site_cache_version( $prefix );
 
-		return WP_APC_KEY_SALT . ':' . $this->abspath . ':' . $prefix . ':' . $group . ':' . $key . ':v' . $site_version . '.' . $group_version;
+		return WP_CACHE_KEY_SALT . ':' . $this->abspath . ':' . $prefix . ':' . $group . ':' . $key . ':v' . $site_version . '.' . $group_version;
 	}