PHP 8.4 Script Troubleshooting & Updates

Fix/Update PHP script for PHP 8.4

I have a PHP script works under PHP 7.4 but has some issues under PHP 8.4
I have a virtual server I can give access for your solutions.
If you manage this stage I have some additional tasks for script improvement under another contract.

What I could manage to find myself - this piece of code
if (isset($request['shipment'])) {
$where['shipment'] = ' AND shipment IN ('.implode(',', $request['shipment']).')';
}
using SAME search parameters/configs/everything same ! - produces test SPHINX query
under PHP 7.4 (see - ...AND shipment IN (1,2) )
/* Wed Jul 30 02:57:06.335 2025 conn 83 real 0.000 wall 0.000 found 3 */ SELECT INTERVAL(price,200,400,600,800) AS value, COUNT(*) AS count FROM w2eth WHERE MATCH('zztop') AND shipment IN (1,2) GROUP BY value ORDER BY value DESC;
but under PHP 8.4 (see - ...AND shipment IN (2) )
/* Wed Jul 30 03:00:43.555 2025 conn 75 real 0.000 wall 0.000 found 2 */ SELECT INTERVAL(price,200,400,600,800) AS value, COUNT(*) AS count FROM w2eth WHERE MATCH('zztop') AND shipment IN (2) GROUP BY value ORDER BY value DESC;
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but it also could be associated with deprecated /vendor environment (SLIM, ZEND, TWIG) - what also should be fixed if possible.
The task is to solve the mentioned issue.
If you're interested - I invite you to start a discussion and I'll give you more details for your consideration and understanding before a contract.
Best regards,