diff --git a/api/src/Mail/Account.php b/api/src/Mail/Account.php
index e580818d63..9d44aad2e8 100644
--- a/api/src/Mail/Account.php
+++ b/api/src/Mail/Account.php
@@ -898,7 +898,7 @@ class Account implements \ArrayAccess
 	 */
 	public static function check_access($rights, $account)
 	{
-		if (!is_array($account) && !is_a($account, 'Account'))
+		if (!is_array($account) && !($account instanceof Account))
 		{
 			throw new Api\Exception\WrongParameter('$account must be either an array or an Account object!');
 		}
diff --git a/api/src/Mailer.php b/api/src/Mailer.php
index 73656958d8..711dff869f 100644
--- a/api/src/Mailer.php
+++ b/api/src/Mailer.php
@@ -107,7 +107,7 @@ class Mailer extends Horde_Mime_Mail
 	 */
 	function  setAccount($account=null)
 	{
-		if (is_a($account, 'Mail\Account'))
+		if ($account instanceof Mail\Account)
 		{
 			$this->account = $account;
 		}