Tokaido provides built-in support for either PHP 7.1 or PHP 7.2. You can switch the running PHP version really easily with the following command:
tok config-set tokaido phpversion 7.1
tok config-set tokaido phpversion 7.2
After you make this change, you'll need to run
tok rebuild to restart your environment.
WarningTokaido does not provide support for PHP 5.6. PHP 5.6 is no longer supported. You should urgently upgrade your old PHP 5.6 sites to at least PHP 7.1.