Docker Postgres Upgrade

[SANDMAN]

I have a Zabbix 6.4.3 stack. It uses Postgres 15.3 database.

Trying to upgrade to zabbix 7.0 and Postgres 16.3 database.

Using other Postgres guides as Zabbix documentation doesn't seem to discuss Postgres upgrade procedures.

https://www.zabbix.com/documentation/current/en/manual/installation/upgrade/containers

I export db via:
docker exec -it zabbix-docker-postgres-server-1 pg_dumpall -U username > upgrade_backup_15.sql

Changed the db path in docker compose 1 folder deeper.
/home/docker/zabbix-docker/zbx_env/var/lib/postgresql/data/16.3

start zabbix 7 stack with empty db. Creates zabbix db + user/pass.
Shutdown stack.

Start only Postgres service.

cat upgrade_backup_15.sql | docker exec -i zabbix-docker-postgres-server-1 psql -d zabbix -U username

spams invalid command /n and finally stops with "out of memory"
What is different from guide I'm following is the previous command would not execute with specifying the database: -d zabbix

Obviously not doing this correctly. Any help on how to properly upgrade Zabbix database Postgres 15.3 to 16.3

Thank you.

[SANDMAN]

I don't understand it but the solution was to NOT start the entire 7.0 stack (which creates new zabbix DB) and then shutting down all containers except postgres-server 16.x, and then importing.
Entire 7.0 Zabbix stack should NOT run until after DB imported into Postgres 16.x

My Steps:
stop all zabbix containers except postgres-server 15.x
export db with pg_dumpall (docker exec -it zabbix-docker-postgres-server-1 pg_dumpall -U username > upgrade_backup_15.sql)
Stop postgres-server 15.x
Edit docker-compose host's postgres-server data directory to a new empty directory + set new version 16.x tag
Start only postgres-server 16.x container (using same zbx_env) (Creates fresh db)
Import db (cat upgrade_backup_15.sql | docker exec -i zabbix-docker-postgres-server-1 psql -d zabbix -U username) - No errors upon import
Start entire 7.0 stack - On first run I saw additional DB upgrade progress + successful

My stack images:
postgres:16.3-alpine
zabbix/zabbix-server-pgsql:alpine-7.0-latest
zabbix/zabbix-web-nginx-pgsql:7.0-alpine-latest
zabbix/zabbix-agent:alpine-7.0-latest
zabbix/zabbix-java-gateway:alpine-7.0-latest