Issue while installing magento 2 .php version 8.1.1

Question

Fatal error: During inheritance of Countable: Uncaught Exception: Deprecated Functionality: Return type of Laminas\Http\Headers::count() should either be compatible with Countable::count(): int, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in C:\xampp\htdocs\magento2\vendor\laminas\laminas-http\src\Headers.php on line 385 in C:\xampp\htdocs\magento2\vendor\magento\framework\App\ErrorHandler.php:61

Answer 1

The problem may come from not matching your PHP version with your Magento version.

System requirements If you are working on an Adobe Commerce cloud infrastructure project, see Service versions in the Cloud Guide. This table notes software versions that were officially tested and supported at the time of the Magento version's release. Newer versions of required software may work but have not been tested. https://devdocs.magento.com/guides/v2.4/install-gde/system-requirements.html