Hello, thanks for the user-friendly interface for editing usernames!

Today I tried to use you plugin in multisite web and found that after changing $this->db->prefix to $this->db->base_prefix in init.php file it works fine with it.

I apologize if I did not take into account some feature and in fact this is not an exhaustive solution. In any case, it would be very cool to get multisite support in the next version)