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

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.