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Don’t be surprised if you have seen the Certificate Update in the Amazon Relational Database Service (Amazon RDS) console.
If you use or plan to use Secure Sockets Layer (SSL) or Transport Layer Security (TLS) with certificate verification to connect to your database instances of Amazon RDS for MySQL, MariaDB, SQL Server, Oracle, PostgreSQL, and Amazon Aurora, it means you should rotate new certificate authority (CA) certificates in both your DB instances and application before the root certificate expires.