Extension MultiSafePay gives 500 error

-- url of the page with the problem -- : swann.eu
-- HikaShop version -- : 6.3.0
-- Joomla version -- : 6.0.3
-- PHP version -- : 8.4

Hi,
Is there anything that could cause sudden 500 errors when using this plugin:
www.hikashop.com/support/documentation/4...ltisafepay-form.html ?

Maybe not compatible with Joomla 6?

It is not used very often but looks very recent that this happend.

Hi, I got some error messages that appear in the console when trying to pay. I hope they are helpfull :

Warning: Undefined array key 0 in /home/www/public_html/administrator/components/com_hikashop/classes/currency.php on line 1126

Warning: Attempt to read property "currency_percent_fee" on null in /home/www/public_html/administrator/components/com_hikashop/classes/currency.php on line 1131

---
Deprecated: GuzzleHttp\Promise\queue(): Implicitly marking parameter $assign as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/promises/src/functions.php on line 24

Deprecated: GuzzleHttp\Promise\each(): Implicitly marking parameter $onFulfilled as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/promises/src/functions.php on line 260

Deprecated: GuzzleHttp\Promise\each(): Implicitly marking parameter $onRejected as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/promises/src/functions.php on line 260

Deprecated: GuzzleHttp\Promise\each_limit(): Implicitly marking parameter $onFulfilled as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/promises/src/functions.php on line 285

Deprecated: GuzzleHttp\Promise\each_limit(): Implicitly marking parameter $onRejected as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/promises/src/functions.php on line 285

Deprecated: GuzzleHttp\Promise\each_limit_all(): Implicitly marking parameter $onFulfilled as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/promises/src/functions.php on line 307

Deprecated: MultiSafepay\Sdk::__construct(): Implicitly marking parameter $httpClient as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/multisafepay/php-sdk/src/Sdk.php on line 38

Deprecated: MultiSafepay\Client\Client::createPostRequest(): Implicitly marking parameter $requestBody as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/multisafepay/php-sdk/src/Client/Client.php on line 110

Deprecated: MultiSafepay\Client\Client::createPatchRequest(): Implicitly marking parameter $requestBody as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/multisafepay/php-sdk/src/Client/Client.php on line 133

Deprecated: Psr\Http\Message\UploadedFileFactoryInterface::createUploadedFile(): Implicitly marking parameter $size as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/psr/http-factory/src/UploadedFileFactoryInterface.php on line 27

Deprecated: Psr\Http\Message\UploadedFileFactoryInterface::createUploadedFile(): Implicitly marking parameter $clientFilename as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/psr/http-factory/src/UploadedFileFactoryInterface.php on line 30

Deprecated: Psr\Http\Message\UploadedFileFactoryInterface::createUploadedFile(): Implicitly marking parameter $clientMediaType as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/psr/http-factory/src/UploadedFileFactoryInterface.php on line 30

Deprecated: MultiSafepay\ValueObject\CartItem::addUnitPrice(): Implicitly marking parameter $taxRate as nullable is deprecated, the explicit nullable type must be used instead in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/multisafepay/php-sdk/src/ValueObject/CartItem.php on line 97

Fatal error: Declaration of GuzzleHttp\Psr7\Request::getProtocolVersion() must be compatible with Psr\Http\Message\MessageInterface::getProtocolVersion(): string in /home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/psr7/src/MessageTrait.php on line 24

---
FatalError
Compile Error: Declaration of GuzzleHttp\Psr7\Request::getProtocolVersion() must be compatible with Psr\Http\Message\MessageInterface::getProtocolVersion(): string
---
Show exception properties

Symfony\Component\ErrorHandler\Error\FatalError {#3514 ▼
-error: array:4 [▼
"type" => 64
"message" => "Declaration of GuzzleHttp\Psr7\Request::getProtocolVersion() must be compatible with Psr\Http\Message\MessageInterface::getProtocolVersion(): string"
"file" => "/home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/psr7/src/MessageTrait.php"
"line" => 24
]
}

---
/home/www/public_html/plugins/hikashoppayment/multisafepay/vendor/guzzlehttp/psr7/src/MessageTrait.php:24

Hi, is the information that I provided of any use? Happy to provide anything else if you need it.