I've been ignoring all of my Amazon AWS Emails about major/minor version upgrades for quite some time now (they always seem rather frivolous), but the email that did catch my eye was my monthly BILL (jumping 4x in costs in the last month or so). Turns out RDS Extended Support for old versions of MySQL costs $0.10 per hour ($75/month) for each end-of-life database. Now, I have not touched my AWS configurations for over 5 years, so it definitely took me some time to get reacquainted to all of the options and
Here's my step-by-step guide on how to successfully upgrade your instances and check your DB connections are still working.
Current Option Group (default:mysql-5-7-db-randomhash-upgrade) is non-default. You need to explicitly specify a new Option Group in this case (default or custom) To solve this error above, I first changed the "Modify" -> Option group from "default:mysql-5-7-db-randomhash-upgrade" to default:mysql-5-7 and also unchecked Enable auto minor version upgrade , which created this invalid option group in the first place. Apply changes and wait for the Status to turn green. Finally, we're ready to do the final step