You likely need to replace the camera with a newer model for Sync 3 from a Sync 3 Escape. There are various threads about this on EU Escape/Kuga sites.
As far as moving to Sync 3.4 on a 2013 Escape, I would not advise this as the vehicle is clearly not designed for this, although some folks have had various levels of success. I would advise installing the latest version of Sync 3.0 first as opposed to 3.4 and see if that is what you are looking for. You will need to perform a 2-step installation to go to Sync 3.0.23219, because Ford broke the installation process from previous CarPlay versions to present.