AWS RDS PostgreSQL DB server OS version

When you create an Amazon RDS for PostgreSQL instance with version 16.8, you don't have direct access to or control over the underlying operating system. Amazon RDS is a managed service where AWS handles the operating system management, patching, and maintenance.

PostgreSQL 16.8 is one of the latest minor versions supported by Amazon RDS for PostgreSQL. This version was released to address regressions from a previous release and includes security vulnerability fixes and bug fixes added by the PostgreSQL community.

If you need to know specific details about the operating system for compliance or compatibility reasons, it's worth noting that RDS for PostgreSQL runs on Amazon Linux, but the exact version and configuration are managed by AWS as part of the RDS service. When connecting to your PostgreSQL 16.8 database and running a version query, you would see information about the PostgreSQL version and compilation environment, but you wouldn't have direct access to OS-level commands or configurations.

You can use automatic minor version upgrades to keep your PostgreSQL 16.8 database updated with the latest patches during scheduled maintenance windows.
Sources
Amazon RDS for PostgreSQL supports minor versions 17.4, 16.8, 15.12, 14.17, 13.20 - AWS
Available PostgreSQL database versions - Amazon Relational Database Service