Omeka-S upgrade error from 1.4.0 to 2.0.0

Omeka S Installing
1

How can I fix this error :

Parse error: syntax error, unexpected ‘?’, expecting variable (T_VARIABLE) in /vendor/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php on line 137

2

Omeka S 2.0.0 (and the current latest version, 2.0.2) requires PHP 7.1 or higher.

You’re getting this error because the PHP installed on your server is older than that.

3

Thank you for this information
I will try to active the correct PHP Version

Serge Normand