The latest version of the Meta Box premium extensions is safe to be included in themes or plugins. There are 2 ways to do that:

#Using TGM Activation Class

This method is highly recommended. Please follow these steps:

  1. Include the TGM Activation Class files into your themes/plugins.
  2. Download the TGM Activation Class.
  3. Add the following code into your theme’s functions.php file or your plugin’s main file

Remember to change the extension slug and name to the correct slug and name of the extension(s) you want to include.

For more information about the syntax, please read TGM Activation Class’s documentation.

#Include the extension directly

In order to include the extension directly in your theme or plugin, please follow the following steps:

  1. Copy the plugin folder to your theme/plugin. It doesn’t matter if you put it in the theme root folder or in a subfolder.
  2. Include the extension’s main file by putting the following line into the functions.php of your theme or your plugin’s file:
require get_template_directory() . '/extension-slug/extension-slug.php'; // Path to the extension's main file

Remember to change the extension slug to the correct slug of the extension(s) you want to include.