I am guessing that you are using a test directory such as /new_shop and test database with a "copy" of your Live site database in it to "practice" upgrading your site ...
Make sure that you have a copy of your Live Site's files:
/includes/configure.php
/admin/includes/configure.php
And that you copied those to:
/new_shop/includes/configure.php
/new_shop/admin/includes/configure.php
And then edited the paths and database name, username and password to reflect the NEW SHOP path for /new_shop and the new database ...
And that you did backup the Live Shop database and load it into the NEW SHOP database so that it can be UPGRADED on your first test through of this ...