Hi all we get notification from AWS, Beginning 8 April 2019 AWS will automatically upgrade the RDS Postgres during maintenance window, this is because PostgreSQL versions 10.6, 9.6.11, 9.5.15, and 9.4.20 contain important cumulative security fixes, and AWS will end the support on 22 April 2019 for PostgreSQL minor versions older than 10.6, 9.6.11, 9.5.15, and 9.4.20, here's the detail of affected version and version to patch the security fixes:
9.4.x to PostgreSQL 9.4.20
9.5.x to PostgreSQL 9.5.15
9.6.x to PostgreSQL 9.6.11
10.x to PostgreSQL 10.6
After querying our RDS Postgres instance in tvlk-prod account, we found lots of our database will be impacted by this upgrade see [1]. We already create schedule to do the upgrade in 3 batches to minimize the impact on our system. The 1st batch will be on Mon, 25 March 2019, 2nd batch Mon, 01 April 2019, 3rd batch Mon, 08 April 2019. We give option to service owner to change the batch for their service (In case some service have event like promo in near time), by comment in this post before Friday, March 22, 2019 at 11.00 AM.