As of this week I have completed all the prerequisites that I need to upgrade my Microsoft SQL Server database on AWS RDS. I am going to complete the actual upgrade using the CLI via PowerShell. I will be (1) upgrading my INSTANCE TYPE from an R5 to an R6i and (2) upgrading my SQL Server 2019 Enterprise version to SQL Server 2022 Enterprise.
Prerequitie Set Up
To start, one of the prerequisites I have already completed is to create a new PARAMATER GROUP for the upgraded version. I have named my parameter group database-rds2022-paramgroup16. I reviewed how I set up a previous parameter group in my post https://lovethesql.com/set-up-parameter-group-on-aws-rds/ from May of 2024.
I also reviewed my post https://lovethesql.com/aws-rds-ssrs-email-subscription-set-up/ at STEP 4 for setting up a new OPTION GROUP and mirrored the features I currently use in my old OPTION GROUP. I have named the new option group database-rds2022-optiongroup16.
UPGRADE to R6i
Before I start the upgrade of the underlying EC2 instance(s), I will take a FULL BACK UP of all my databases and a snapshot of the server. Once that is completed, I will open POWERSHELL and run the following code.
aws rds modify-db-instance --db-instance-identifier ProductionSqlRds01 --db-instance-class db.r6i.2xlarge --apply-immediately
Sit back and relax while AWS does its thing. Time will depend on the size of your system. This completed in about thirty minutes for me.

The status AVAILABLE will change to MODIFYING and then it may later change to other things like OPTIMIZING and BACKING UP.
UPGRADE to SQL SERVER 2022
Once the instance sizing completes, it should have made a SNAPSHOT. I will check and verify the snapshot was successful and if not I’ll again make a snapshot of the server and then proceed to the Server 2022 upgrade.
If I’ve done everything correctly, I can just run this code and sit back and watch for about two to four hours.
aws rds modify-db-instance --db-instance-identifier ProductionSqlrds01 --db-parameter-group-name database-rds2022-paramgroup16 --option-group-name database-rds2022-optiongroup16 --allow-major-version-upgrade --engine-version 16.00.4165.4.v1 --apply-immediately

The status AVAILABLE will change to UPGRADING and then it may later change to other things like OPTIMIZING and BACKING UP.
Next, I will verify my applications can connect and that my other feature I added in the OPTION GROUPS are working, like SSIS and SSRS.
Lastly, I want to clean up my settings and relock the ability for an automatic major version upgrade.
aws rds modify-db-instance --db-instance-identifier ProductionSqlrds01 --no-allow-major-version-upgrade --apply-immediately
end.