Note that in this update, PostgreSQL will be updated from 17.5-5 → 18.1-1. PostgreSQL databases don’t generally update automatically, so it is maybe a good time to make a backup, while waiting for the warning to be removed.
See the PostgreSQL docs for ways to upgrade: PostgreSQL: Documentation: 18: 18.6. Upgrading a PostgreSQL Cluster
I generally dump all the data, create new databases, and import all the data. To dump the data from a database I use:
pg_dump -Z 9 -f dump-file-name.sql.gz database-name
After upgrading and creating a fresh database, populate the database with the saved data:
cat dump-file-name.sql.gz | gunzip | psql database-name