Rule source on GitHub

DowngradeStrEndsWithRector

Downgrade str_ends_with() to strncmp() version

-str_ends_with($haystack, $needle);
+"" === $needle || ("" !== $haystack && 0 === substr_compare($haystack, $needle, -\strlen($needle)));

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\DowngradePhp80\Rector\FuncCall\DowngradeStrEndsWithRector;

return RectorConfig::configure()
    ->withRules([
        DowngradeStrEndsWithRector::class,
    ]);