Amazon RDS has published new SSL/TLS certificates for connecting to your RDS databases. The current certificates will expire on March 5th, 2020.
All Vapor users using RDS databases in their projects should update their instances to the new certificates.
You should ensure your Vapor project requires the latest versions of the laravel/vapor-cli and laravel/vapor-core packages. After that, you may refer to Amazon's instructions to update your instance's certificates using the AWS console.