@Gargron @freemo It's pretty respectable that you've been keeping a Postgres 9 based instance running for that long, with all of its patches, and have been able to do zero downtime updates. 🥂

I've never had to do a zero downtime upgrade from major postgres versions. Since 2016 I've worked at shops that only use RDS (nice, but expensive/locks you to Amazon, which is a terrible company)

If some shop wrote a way to do streaming updates from 9->13, it's probably closed, internal and proprietary