This paragraph provides a detailed overview of sending a Unicode message using the Vonage PHP SDK and Symfony Framework. The author created a simple application that uses the Messages API to send a Greek Unicode message from a Viber device. They bootstrapped a full Symfony framework with Docker, added the Vonage PHP SDK as a dependency, configured the credentials, and used the Messages Sandbox to test the application. The code demonstrates how to extract the message payload, create a ViberText object, and send the message using the Vonage Client. The author also implemented defensive coding by introducing a try-catch block to handle exceptions and logging errors with Symfony's Monolog logger.