Copy-pasting the PHP send-SMS example from Infobip's interactive IDE (tryapi.infobip.com) into a project on infobip-api-php-client 5.0 crashed with an undefined method call: ObjectSerializer::sanitizeForSerialization does not exist (removed in 5.0), and further down the same class the config getters like getApiKeyWithPrefix were also gone. PHP 8.2, Symfony 6.2. The IDE examples were stale, written against the v4 API surface.