Any software to help change PHP5.6 scripts to PHP7.4 compatible?

[nyrian]

I have a few dozen PHP files that are running fine under PHP5.6 on the server. As soon as I change to PHP7 (any variant) all the website pages crash. So I'm guessing there are some incompatible bits. How do I find them? I've just been reading through:

PHP: Changed functions - Manual

PHP is a popular general-purpose scripting language that powers everything from your blog to the most popular websites in the world.

www.php.net

and the 'deprecated' section but most of that doesn't appear in any of my scripts. Is there a good program, online tool, or list to help me find the sections that need to be changed in each script?

Any help appreciated.

 

[BigDady]

Here is some help https://www.php.net/manual/en/migration70.php
And having looked here I think this is where I'd start https://auth0.com/blog/migrating-a-php5-app-to-7-part-three/
It talks of php7mar to help in the migration.