Well, my installation is based on the official deb package. However, you cannot automatically upgrade from 2.2 to 2.3. I think this is because graylog might change things overtime and they don’t want to break things without administrator’s supervision.
So you need to download and dpkg -i to install it manually.
You should also check upgrading to 2.3.x docs where they describe changes that may impact your configuration.
For my case, I decide to upgrade and replace my existing graylog.conf with the maintainer’s configuration. Then, copy password hashes from the existing one to the new one.
It runs smoothly though.