Hey, whats up...
I had the same issue as you... after I updated my WP both front and backend it stoped working.
I debugged the code and change only one line and works fine for me.
On wptap-mobile-detector/md-includes/function.php
I changed "mobileDetect()" function and put only a if clause.
if($mobile_current_id!=NULL){
$mobilemeta = $wpdb->get_row("SELECT theme_template,redirect FROM ".TABLE_MOBILEMETA." WHERE mobile_id=".$mobile_current_id);
if($mobilemeta->redirect) {
header("Location: $mobilemeta->redirect");
exit;
}
return $mobilemeta->theme_template;
}
Maybe will help you too...