Deprecation: #71249 - Deprecate render method of FlashMessage class

See Issue #71249

Description

Method TYPO3\CMS\Core\Messaging\FlashMessage::render() has been marked as deprecated.

Affected Installations

Instances with custom backend modules that use this method.

Migration

Use custom render code, the <f:flashMessage /> ViewHelper or the ModuleTemplate for backend modules to render FlashMessages. It is suggested not to include HTML in flash messages. Flash messages should be short notifications on user interactions. If you need more elaborate or persistent messages, use <f:be.infobox /> view helper or HTML similar to that.