Configure log steams from beanstalk using the new format?

The older CloudWatch Logs agent, supports the collection of logs from only servers running Linux. If you're already using that agent, you can continue to do so. However, the older agent requires Python 2.7, 3.0, and 3.3. Because current EC2 instances do not use those versions of Python and those versions are deprecated and are no longer being patched, AWS strongly recommend that you migrate to the unified CloudWatch agent.

Elastic Beanstalk integration with CloudWatch Logs doesn't directly support the streaming of log files that your application generates. So I am assuming that you are trying to log custom files and not the defaults called out per platform within the AWS docs.

If your need is specific to custom logs then install the unified agent through use of an ebextension that simply installs the amazon-cloudwatch-agent package. If you are not familiar with customising the agent a quick and easy way is to run the wizard. You can then have an ebextension start the agent using a saved version that the wizard generated or even start the agent and reference the configuration from the SSM Parameter Store which the wizard can upload config files to.