As a first step I'd suggest that the Octopus Manager GUI could have a "download latest version"-button. This would make the upgrade a lot smoother.

You can just use chocolatey for a single command line upgrade. It even works well with multiple instances (we have 9 on a single server that it's been working fine with)
cup OctopusDeploy -y

For anyone else discovering this later, someone added a step template in the community library for updating Octopus through Octopus: https://library.octopus.com/step-templates/4b3a1f09-1827-41bb-88a4-894c6317922b. You can easily use an edited version of that script to update directly on the server as well if you have access (e.g. I run it on a scheduled task).

This would be really useful - I love that we get frequent updates, but it is a bit of a faff having to download an installer, run it on the server and then push upgrades manually to all the tentacles and calamari as well (which you seem to have to do separately?) every time!

Would love this, in addition to an automatic update setting, we have so many updates (and I love it) but the process is so smooth it could be automated.

This may help some... I've created a 2 step octopus process to do this; the first step pulls down the msi package wraps it in a nugget and pushes it to the octopus repo. The 2nd step turns on maintenance mode, deploys the nugget, installs the msi, then turns maintenance off. I did it like this to ensure the same package goes to the test and live environment and can be done by the users of octopus. It would be far easier if the feature was built in.

oh so much this. currently stuck in a terrible bureaucracy where things are so locked down, being able to click an "upgrade now" button would make life so nice instead of having to explain what I want to do and why i want to do it, and then explain to someone else how to upgrade the octopus server for me. because god forbid I have access to a "production server" (that "nobody but our team uses")

Agree, since many hotfixes are released lately, this would be a nice feature.

This would be great if we could upgrade from the WebUI. Similar to how some other windows packages do it like PRTG.

I'd agree with Eric that logging into the physical server is not always feasible or even possible. The ability to upgrade the server remotely would be a great addition.

The users of a system aren't always the administrators of the system. Upgrading the Octopus server requires the participation of the infrastructure team in my organization. I am an administrator in Octopus, but I am not an administrator of the server it runs on. With the recent pace of updates, it would be useful to be able to self-update, rather than request and wait.

Is downloading and double clicking an installer really that bad? The agents are all upgraded via a click in the UI. I think many other features would be much more useful than this one...?