its not udating to joomla4.3 installation errors !

I just bought OSproperty template , it doesn't update to joomla 4 , it keeps giving errors , nothing get passed, I have tried on both xampp and on my website it gives undefined constant jpath ,
when i try the template old joomla 3 it works , can someone please guide , im going around in circles getting fed up , why with purchase updated to atleast joomla4 are not provided or is it me doing something wrong ? 
I'm not migrating from older joomla versions , I'm using joomla 4 upto date.

thanks

Hi Hassan,
In this case, please try to upload your site into live server. Then, please raising new ticket on category OS Property through this link: joomdonation.com/support-tickets.html and provide your site url with super admin account. I will help you to solve the problem.
Thanks
Dam

I have raised ticket, thanks