Need to decrypt this files

Hi! the developer died so no chance to access source code again and I need to update/modify this code.

Thanks a lot in advance.

https://www.virustotal.com/gui/file-analysis/ODFlZjQxZDAxNDZhYzVjOTEyODJmOThjOTgyYzQyMmE6MTc1MzQ5MTE5Mw==

Sorry, forgot to mention ioncube encoded files