We recommend you configure a test instance of your helpdesk to test any major updates before trying to put them live

This is easy to accomplish by following the "Moving Servers" guide:

With the following notes:

1) Disable cron on the test instance before importing your database

To ensure email does not get processed into your test instance, you need to disable the cron job on the test server BEFORE you import your database on the test instance.

You can choose to enable cron again after you have logged-in to the test instance as an admin to disable/delete the active email accounts that exist on your live helpdesk. The point here is that you do NOT want email processing from live email accounts into your test instance. So you need to delete them (and possibly replace them with test accounts) if you want to enable cron on the test instance.

2) Edit config/advanced/config.settings.php

Add the following lines:

$SETTINGS['core.filestorage_method']     = 'db';
$SETTINGS['core.filestorage_s3_key']     = 'x';
$SETTINGS['core.filestorage_s3_secret']  = 'x';
$SETTINGS['core.filestorage_s3_bucket']  = 'x';

This will force the system to store files in the database. This is a safety precaution to ensure if you are using some other mechanism like S3, that deleting a file in this test instance does not delete the file in S3 which would still be in use by your live helpdesk.

You may also wish to enable the disable_outgoing_email option in this file to disable all outgoing email (e.g. this will ensure end-users don't get test emails etc).