Fatal error: Uncaught Error: Call to undefined function Slim\\Http\\get_magic_quotes_gpc()

Question

I don't know what to do anymore.

Probably my site refuses to serve (Error 500) after PHP update. I had to do it due to the addition of another page that required it.

When I click on the button that is supposed to display the entered data, I get a POST example.com/api/src/index.php/search 500 (Internal Server Error) in the F12 console.

I also use angularjs. To the right of the error displays: angularjs:9287. This line is: xhr.send(post || null);

Server logs:

PHP Fatal error: Uncaught Error: Call to undefined function Slim_magic_quotes_gpc() in api/vendor/slim/slim/Slim/Http/Util.php:60

What should I do? How do I fix it?

Thank you in advance to literally everyone for your guidance.

I tried composer update and slimframework with psr7. I did it on localhost and uploaded it to the hosting - swapped the main folder.