pdo_dblib library (driver for sqlserver) in PHP6 and PHP7

Hello,

I am installing a application over (RHEL6.8) , which needs PHP 5.6+ and has the arquitecture (apache --> php --> sqlserver(Windows 2008R2)). I see that with PHP 5.3.3 this driver is (php-pdo_dblib), but I don't see it with other PHP version.
¿where could I find this library?

thanks for all,