New postgres image version is available on docker registry with tag 12-debezium - https://hub.docker.com/r/openlmis/postgres/tags

Upgrade instructions for each version can be found on postgres page https://www.postgresql.org/docs/current/upgrading.html

In order to properly upgrade database additional steps might be required, depending on the deployed instance:

It is recommended to make full backup before any upgrade to prevent data loss.