Important: #105653 - Require a template filename in extbase module template rendering 

Description 

With the introduction of the FluidAdapter in TYPO3 v13, the dependency between Fluid and Extbase has been decoupled. As part of this change, the behavior of the ModuleTemplate::renderResponse() and ModuleTemplate::render() methods has been adjusted.

The $templateFileName argument is now mandatory for the ModuleTemplate::renderResponse() and ModuleTemplate::render() methods. Previously, if this argument was not provided, the template was automatically resolved based on the controller and action names. Starting from TYPO3 13.4, calling these methods with an empty string or without a valid $templateFileName will result in an InvalidArgumentException.

Extensions using Extbase backend modules must explicitly provide the $templateFileName when calling these methods. Existing implementations relying on automatic template resolution need to be updated to prevent runtime errors.

Example:

Before:

$moduleTemplate->renderResponse();

After:

$moduleTemplate->renderResponse('MyController/MyAction');

Note, that it is already possible to explicitly provide the $templateFileName in TYPO3 12.4. It is therefore recommended to implement the new requirement for websites using TYPO3 12.4.