AbanteCart core v.1.4.4 Interface "Psr\Http\Message\StreamInterface" not found

[timlight10]

After updating to 1.4.4, customers cannot complete the checkout process, the fast checkout hangs with a blank screen, or they cannot select a shipping method.

In the error log there is this:

Code Select Expand

2026-05-09 13:49:32 - Unknown Error: AbanteCart core v.1.4.4 Interface "Psr\Http\Message\StreamInterface" not found
Full stack trace:

Code Select Expand

2026-05-09 13:49:32 - Unknown Error: AbanteCart core v.1.4.4 Interface "Psr\Http\Message\StreamInterface" not found
Trace:
#0 /home4/juliann7/public_html/dps/vendor/composer/ClassLoader.php(576): include()
#1 /home4/juliann7/public_html/dps/vendor/composer/ClassLoader.php(427): {closure:Composer\Autoload\ClassLoader::initializeIncludeClosure():575}('/home4/juliann7...')
#2 /home4/juliann7/public_html/dps/extensions/ups/core/ups_sdk/vendor/guzzlehttp/psr7/src/Utils.php(310): Composer\Autoload\ClassLoader->loadClass('GuzzleHttp\\Psr7...')
#3 /home4/juliann7/public_html/dps/extensions/ups/core/ups_sdk/vendor/guzzlehttp/psr7/src/Request.php(57): GuzzleHttp\Psr7\Utils::streamFor('grant_type=clie...')
#4 /home4/juliann7/public_html/dps/extensions/ups/core/ups_sdk/OAuthClientCredentials/src/Request/OAuthClientCredentialsApi.php(384): GuzzleHttp\Psr7\Request->__construct('POST', Object(GuzzleHttp\Psr7\Uri), Array, 'grant_type=clie...')
#5 /home4/juliann7/public_html/dps/extensions/ups/core/ups_sdk/OAuthClientCredentials/src/Request/OAuthClientCredentialsApi.php(122): UPS\OAuthClientCredentials\Request\OAuthClientCredentialsApi->createTokenRequest('client_credenti...', '366R15')
#6 /home4/juliann7/public_html/dps/extensions/ups/core/ups_sdk/OAuthClientCredentials/src/Request/OAuthClientCredentialsApi.php(103): UPS\OAuthClientCredentials\Request\OAuthClientCredentialsApi->createTokenWithHttpInfo('client_credenti...', '366R15')
#7 /home4/juliann7/public_html/dps/extensions/ups/core/utils.php(65): UPS\OAuthClientCredentials\Request\OAuthClientCredentialsApi->createToken('client_credenti...', '366R15')
#8 /home4/juliann7/public_html/dps/extensions/ups/storefront/model/extension/ups.php(366): ups\core\getUPSAccessToken(Object(Registry))
#9 /home4/juliann7/public_html/dps/extensions/ups/storefront/model/extension/ups.php(187): ModelExtensionUps->processRequest(Array, '25', '10', '11', '16')
#10 /home4/juliann7/public_html/dps/storefront/controller/responses/checkout/pay.php(1791): ModelExtensionUps->getQuote(Array)
#11 /home4/juliann7/public_html/dps/storefront/controller/responses/checkout/pay.php(374): ControllerResponsesCheckoutPay->select_shipping(NULL)
#12 /home4/juliann7/public_html/dps/core/engine/dispatcher.php(306): ControllerResponsesCheckoutPay->main()
#13 /home4/juliann7/public_html/dps/core/engine/response.php(87): ADispatcher->dispatch()
#14 /home4/juliann7/public_html/dps/core/engine/router.php(222): ATypeResponse->build('checkout/pay')
#15 /home4/juliann7/public_html/dps/core/engine/router.php(86): ARouter->route()
#16 /home4/juliann7/public_html/dps/index.php(82): ARouter->processRoute('r/checkout/pay')
#17 {main} in /home4/juliann7/public_html/dps/extensions/ups/core/ups_sdk/vendor/guzzlehttp/psr7/src/Stream.php on line 12
Any advise?