Please, ask your host in the first place or check their FAQ.

Usually, adding a line in the .Htaccess at the root of GuppY will do, or select PHP 5 in the management console of your online space.

Here are some examples:

Nuxit v2
Choice avalaible in customer's area.

Nuxit v1
Add this into htaccess at the root:
AddHandler x-httpd-php5 .php
AddType application/x-httpd-php5 .php

1Hebergement
Choice avalaible in customer's area.

1 and 1
Add this into htaccess at the root:
AddType x-mapp-php5 .php

Free
Add this into htaccess at the root:
<IfDefine Free>
php56 1
</IfDefine>

OVH
Add a file to the root .ovhconfig with this content:

app.engine=php
app.engine.version=5.6
http.firewall=none
environment=production

Online.net
Add this into htaccess at the root:
AddType application/x-httpd-php5 .php


This list is not exhaustive and only serves for example purpose. If you have other instances, thank you for letting us know.