osTicket 1.12 requires PHP 5.6+

The same happens to me with PHP 5.6.40-5 and ubuntu14.04.1

Did you restart the webservice after you changed PHP version?

I dont changed the PHP version

I feel like I am talking in circles then...

You said:

You need to upgrade the server to 5.6 or higher.
And you need to make sure that the webserver is using the new version.