Upgrading from 8.7.5 to 10.1.3 - what do I need to worry about?

We are planning on upgrading our GitLab instance from 8.7.5 to 10.1.3. I’ll make the usual backups of gitlab.rb and gitlab-secrets.json, but I was wondering if there is anything else I need to worry about as part of the upgrade. Thanks in advance.

If you are using external database, be sure to upgrade the database version too. Also, if you’re using mysql, some feature will become limited.

I’m using the PostgreSQL DB that ships with the Omnibus installation. I was wondering if I could update the DB while still on 8.7.5 or do I have to upgrade the DB and GitLab in one shot. In another words, will 8.7.5 run with a version of PostgreSQL newer than 9.2?