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PHP 7.4.x is required for FreePBX 16.
Before we start upgrade tool, we have to upgrade system PHP to 7.4
If you are using Debian then you could refer/follow "Install FreePBX 16.0 on Debian" wiki guide to update PHP version to 7.4.
Please note that, for an existing system we just have to update the PHP version not all the dependent other system packages.
Update to SURY repository process to update PHP 7.4.x would be enough for an existing Debian system.
use "php -v" command in Linux cli to confirm the PHP version.
Code Block root@vultr:/var/www/html/admin/libraries# php -v PHP 7.4.22 (cli) (built: Jul 30 2021 13:09:18) ( NTS ) Copyright (c) The PHP Group
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