PHP Runtime Deprecation Notice: Creation of dynamic property
Using version 12.0.1:
PHP Runtime Deprecation Notice: Creation of dynamic property SBublies\Gridtocontainer\Controller\MigrationController::$moduleTemplateFactory is deprecated in /var/www/html/app/site/vendor/sbublies/gridtocontainer/Classes/Controller/MigrationController.php line 46
adding
protected $moduleTemplateFactory;
protected $moduleTemplate;
would solve it
Edited by Georg Ringer