Plugin Wptap Mobile Error

Hi All ,
I have a small issue with plugin when I install it on wordpress configure and try to put on i have a critical error
“

Fatal error: Uncaught Error: Call to undefined function md_pluginname() in exemple/public_html/wp-content/plugins/wptap-mobile-detector/mobiledetector.php:23 Stack trace: #0 exemple/public_html/wp-admin/includes/plugin.php(1882): include() #1 exemple/public_html/wp-admin/plugins.php(164): plugin_sandbox_scrape(‘wptap-mobile-de…’) #2 {main} thrown in exemple/public_html/wp-content/plugins/wptap-mobile-detector/mobiledetector.php on line 23

What i do:
– I checked version wordpress ( it works on this version i’m 100% sure)
– I checked mobiledetector.php /plugin.php /plugins.php
– I’ve compered with site where the plugin perfectly work – they looks same …
– version of php/wordpress etc. are same on both sites – and still on one plugin works on second no clue why not…
Important – i cannot update wordpress
Pls. help ??