Implement changes done on a newer plugin version.

I have a plush doll personalization website using a woocommerce/wordpress Fancy Product Designer plugin, but I had to adapt it so people could add items to both sides( front and back) at the same time. I´ve hired a programmer who made that on other version of the plugin 1.0.24 and I would like do do it on the last avaliable update. The plugin does almost everything I need, except adding items to front and back of the product at the same time. For example: When the user adds hair to the front of the doll, it automatically puts on the back too. When they add a tshirt, pants or skin textures, right away it shows the front and back of that item on the stage. I can send you my website so you can understand it better how its working now. The plugin website ( without the changes I need to get done) is [login to view URL] I had to pay other professional to do that job for me, and now as they improved a lot the script I would like to update my site. I could send the changes made by the old programmer and the newer version. Thanks in advice!