Upon upgrading you will need to activate the PHP extensions for PHP7 again which XF needs. Most likely mysqlnd, mb_string, curl and stuff like that. Other than that it should work, depending on which version of XF1.5 you are using.
Upon upgrading you will need to activate the PHP extensions for PHP7 again which XF needs. Most likely mysqlnd, mb_string, curl and stuff like that. Other than that it should work, depending on which version of XF1.5 you are using.