Please update to [WordPress version 4.7](https://codex.wordpress.org/Version_4.7)

Click the above link to the WordPress Codex regarding WordPress 4.7 For Developers.

> **Page Templates for Post Types Add support for post type templates.** 
>
> Add support for post type templates. By opening up the page template
> functionality to all post types, theme developers have even more
> flexibility with the WordPress template hierarchy ([read more](https://make.wordpress.org/core/2016/11/03/post-type-templates-in-4-7/)).