I am installing the RedSys module http://www.redsys.es following their guide. At some point of their guide they say the following:
4.Se deben colocar los ficheros de la carpeta “Source”, incluido en el módulo de pago de REDSYS, en el siguiente directorio del módulo de Magento: (TRANSLATION: The Source folder's files must be included in the following Magento's module directory:)
The thing is that they are writing new files in the core, so I wonder whether or not it would be the same if I write these files in local in the folder:
I ask this because I want to avoid problems in future Magento upgrades and I think that if they work the same way then the second approach would be better.