Handling the Error "PHP message: PHP Parse error: syntax error, unexpected" When Upgrading from Kayako Classic Case to Fusion

Overview

When running the setup script to upgrade Kayako Classic from Case to Fusion, the following error may appear:

2020/10/14 13:25:32 [error] 6713#6713: *1 FastCGI sent in stderr: 
"PHP message: PHP Parse error: syntax error, unexpected ':', 
expecting '{' in /var/www/html/fusion/__swift/includes/functions.php on line 1744" 
while reading response header from upstream, client: 10.11.63.19, server: 
kayako4fusion.embl.de, request: "GET /setup/ HTTP/2.0", upstream: 
"fastcgi://unix:/var/run/php5-fpm.sock:", host: "tickets.embl.de"

This article provides information on how to fix this issue.

Information

The most probable cause of this error is that your system does not meet the server requirements for installing the latest version of Kayako Classic particularly the PHP version being used.

To resolve this issue, use only the version of PHP specified in the Kayako Classic Server Configuration and System Requirements article.