My host tested phpinfo.php at https://arnhemseluitjes.net
and indeed php version 5.6.
But when I tested phpinfo.php in the root of my forum https://arnhemseluitjes.netphpBB3/phpinfo.php
which is phpBB 3.1.0-dev, the result is: php version 4.4.9.
As I already mentioned earlier, I managed to upgrade with an older version of my mysql database to phpBB3.2.2 which is at http://arnhemseluitjes.net/luitforum
When I call the php version in this root, which is: http://arnhemseluitjes.net/luitforum/phpinfo.php
I Indeed get PHP Version 5.6.34.
For me this is a mistery I cannot explain. Maybe you can?