The example is for PHP 5.6 as provided by Ondřej Surý repository. The procedure is identical for all PHP versions that are provided by the Ondřej Surý repository. You MUST just adapt the paths according the PHP version that you target.
The path is:
; Configuration for the IonCube Loader ; priority=01 zend_extension=ioncube.so
with the ionCube PHP Loader (enabled) + Intrusion Protection from ioncube24.com (unconfigured) v10.2.1, Copyright (c) 2002-2018, by ionCube Ltd. with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies