No update notification - manual update?

Hi,

I read that nextcloud 18 is available. i have runnung 17.0.2 or 17.2. homever i got no update notification when i log in as administrator.

i think about a manual update as described here: https://docs.nextcloud.com/server/18/admin_manual/maintenance/upgrade.html

So i have to replace everything except /config and /data. but when i do that the directory /apps will be overwritten. that means my installed apps are gone - or am i thinking wrong?