Translation of a self-written PHP site from 5.6 to 7.2

Phased work and payment of 2-4 stages with a git repository and commit at each stage due to the inability to place an order using the Safe Deal service. A small test task.

About the project: php directory site without OOP. Number of lines of code: 22934. Number of PHP files: 78. We will reset the archive of the site files with the git repository and the database dump.

What to do: replace mysql_* with mysqli_*, replace