Magee themes shortcodes crashed my site after I upgraded

I use Magee Themes. I upgraded to WP 4.7 last week. A couple days ago, I switched Magee themes from Alchem to Magee because it had a feature I need. Magee has it’s own plugin called Magee Shortcodes. Since I upgraded to WP 4.7, I can no longer activate the shortcode. When I do, my site crashes with this error code:

Fatal error: Cannot redeclare magee_slider_register() (previously declared in /home/content/71/10618471/html/wp-content/plugins/magee-shortcodes/inc/magee-slider.php:8) in /home/content/71/10618471/html/wp-content/themes/magee/includes/postType-slider.php on line 33

According to Magee, they’ve tested the plugin and they say they have no problems with it. I’m talking to my hosting provider to see what else I can do. They say it’s a WordPress issue. Now I need to know how to fix this so I can build my site. Please advise!!