Migration to localhost for testing

Hello! We have a problem on out website after we updated PHP and the WordPress theme. Some code and functionality that was coded in the original WordPress theme files without a child theme has to be coded again, since a child theme was not used by the one who set up the website originally. We don’t want to take the website back to a former backup, since we have already added much content after we discovered the problem. Therefore I have installed WAMP and try to restore a former backup to localhost to see how the webpage was before the upgrade. I use PHP 5.5 and WordPress 4.9.8, which is what the former backup used and supported. which That will help me to troubleshoot the problem. I followed the instructions at https://updraftplus.com/faqs/how-do-i-migrate-to-a-new-site-location/ but got a 404 error after the restoration. I have mod_rewrite enabled on the Apache server. I did not download the migrator add on, since that did not seem to be required in the tutorial. You can find my changelog at https://www.guttogjente.no/wp-content/uploads/2019/06/changelog.txt. If I should use the migrator, do I need to pay extra for that or is it included? In case, how do I download it?