Multiple PHP and FreeTDS/MSSQL support on CentOS7

I’ve installed two php versions 5.4 and 5.6
In a website, if i select 5.4 I can connect to MSSQL database with PDO support, but with 5.6 i get this error:

Database Exception – yii\db\Exception
could not find driver
Caused by: PDOException

If i check for php56-mssql it seems already installed but in phpinfo() i can’t see FreeTDS support for MSSQL (available if i switch back to 5.4).
Any suggestion?
Thanks in advance