fix #5545
diff --git a/system/libraries/Session/Session_driver.php b/system/libraries/Session/Session_driver.php
index 2fe30b8..a26b3a3 100644
--- a/system/libraries/Session/Session_driver.php
+++ b/system/libraries/Session/Session_driver.php
@@ -121,7 +121,7 @@
 	 */
 	public function php5_validate_id()
 	{
-		if (PHP_VERSION_ID < 70000 && isset($_COOKIE[$this->_config['cookie_name']]) && ! $this->validateId($_COOKIE[$this->_config['cookie_name']]))
+		if (isset($_COOKIE[$this->_config['cookie_name']]) && ! $this->validateSessionId($_COOKIE[$this->_config['cookie_name']]))
 		{
 			unset($_COOKIE[$this->_config['cookie_name']]);
 		}
diff --git a/system/libraries/Session/drivers/Session_database_driver.php b/system/libraries/Session/drivers/Session_database_driver.php
index 074accf..f342690 100644
--- a/system/libraries/Session/drivers/Session_database_driver.php
+++ b/system/libraries/Session/drivers/Session_database_driver.php
@@ -353,7 +353,7 @@
 	 * @param	string	$id
 	 * @return	bool
 	 */
-	public function validateId($id)
+	public function validateSessionId($id)
 	{
 		// Prevent previous QB calls from messing with our queries
 		$this->_db->reset_query();
diff --git a/system/libraries/Session/drivers/Session_files_driver.php b/system/libraries/Session/drivers/Session_files_driver.php
index 654f300..f5925d5 100644
--- a/system/libraries/Session/drivers/Session_files_driver.php
+++ b/system/libraries/Session/drivers/Session_files_driver.php
@@ -402,9 +402,11 @@
 	 * @param	string	$id
 	 * @return	bool
 	 */
-	public function validateId($id)
+	public function validateSessionId($id)
 	{
-		return is_file($this->_file_path.$id);
+		$result = is_file($this->_file_path.$id);
+		clearstatcache(TRUE, $this->_file_path.$id);
+		return $result;
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/libraries/Session/drivers/Session_memcached_driver.php b/system/libraries/Session/drivers/Session_memcached_driver.php
index 9e81168..b464439 100644
--- a/system/libraries/Session/drivers/Session_memcached_driver.php
+++ b/system/libraries/Session/drivers/Session_memcached_driver.php
@@ -303,7 +303,7 @@
 	 * @param	string	$id
 	 * @return	bool
 	 */
-	public function validateId($id)
+	public function validateSessionId($id)
 	{
 		$this->_memcached->get($this->_key_prefix.$id);
 		return ($this->_memcached->getResultCode() === Memcached::RES_SUCCESS);
diff --git a/system/libraries/Session/drivers/Session_redis_driver.php b/system/libraries/Session/drivers/Session_redis_driver.php
index d7a5755..f351aff 100644
--- a/system/libraries/Session/drivers/Session_redis_driver.php
+++ b/system/libraries/Session/drivers/Session_redis_driver.php
@@ -323,7 +323,7 @@
 	 * @param	string	$id
 	 * @return	bool
 	 */
-	public function validateId($id)
+	public function validateSessionId($id)
 	{
 		return (bool) $this->_redis->exists($this->_key_prefix.$id);
 	}