yeah, on Ubuntu based system you need to biuld Csound yourself. It ain't that tricky though. In fact, I think there is now a 6.11 version in the Ubuntu repos. Anyhow, the new build is underway, once it's ready it will show in green at the top of the list. Click on the link and select artefact. Let me know if you have any issues.
[update] Here's the link to the new installer