Joomla 5 has a Backward Compatibility Plugin which helps support code from previous versions of Joomla.
Joomlashack extensions rely on this plugin and it should be enabled when using Joomlashack products.
This plugin is automatically activates for Joomla 5 sites. You'll find it in the "Plugins" area of your Joomla site, as in the screenshot below:
At the moment, our extensions support Joomla 3, 4, and 5. To make this work, we rely on the Backwards Compatibility plugin. Only when we drop support for older versions of Joomla will be able to also drop the requirement to use the Backwards Compatibility plugin.