occ upgrade won't download or install any updates nor will it check for new updates. Please read the documentation how to proceed:
https://doc.owncloud.org/server/9.0/admin_manual/maintenance/upgrade.html
Depending on your initial installation way choose the instructions there and proceed with the update to 9.0.4.
I'm closing here for now for the reasons explained in https://central.owncloud.org/t/why-should-i-create-a-new-thread-for-each-question-problem/1123. If you need further help with the update please create a new thread in the help category for oC 9.0.x