2026-01-29 [error] Class "Http\Adapter\Guzzle6\Client" not found"

[yurg]

Thank you for the extension.
Have got the error after CiviCRM 6.10.0 update on a WordPress 6.9 and had to run $composer upgrade in the extension directory to fix the issue. Consequently got the "abandoned package" message but contributions seem to start working at least.

2026-01-29 07:24:30-0400  [error] 
$Fatal Error Details = array:3 [
  "message" => "Class "Http\Adapter\Guzzle6\Client" not found"
  "code" => null
  "exception" => Error {#3801
    #message: "Class "Http\Adapter\Guzzle6\Client" not found"

trace: {
      /public_html/wp-content/uploads/civicrm/ext/nz.co.fuzion.omnipaymultiprocessor/CRM/Core/Payment/OmnipayMultiProcessor.php:1438 {
        CRM_Core_Payment_OmnipayMultiProcessor->createGatewayObject()
        › $stack->push($history);
        › $this->guzzleClient = HttpPlugClient::createWithConfig(['handler' => $stack]);
        › $this->client = new Client($this->guzzleClient);
      }
      /public_html/wp-content/uploads/civicrm/ext/nz.co.fuzion.omnipaymultiprocessor/CRM/Core/Payment/OmnipayMultiProcessor.php:266 { …}
      /public_html/wp-content/uploads/civicrm/ext/nz.co.fuzion.omnipaymultiprocessor/CRM/Core/Payment/OmnipayMultiProcessor.php:179 { …}
      /public_html/wp-content/plugins/civicrm/civicrm/CRM/Contribute/Form/Contribution/Confirm.php:2693 { …}

and

- Downloading php-http/guzzle6-adapter (dev-master d1c6c9c)
  - Installing php-http/guzzle6-adapter (dev-master d1c6c9c): Extracting archive
Package php-http/guzzle6-adapter is abandoned, you should avoid using it. Use guzzlehttp/guzzle or php-http/guzzle7-adapter instead.
Package php-http/message-factory is abandoned, you should avoid using it. Use psr/http-factory instead.
Generating autoload files
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Found 2 security vulnerability advisories affecting 1 package.
Run "composer audit" for a full list of advisories.
Using version ^2.0@dev for php-http/guzzle6-adapter