It is true MineOS Crux is not officially maintained or supported, but all the same, if you find that you’d like to keep and maintain your existing install, I’ll try where I can to help.
The 0.5.x is definitely not going to be maintained in any sense, so getting newer versions of those scripts I think is not a possibility. That said, since you express interest in upgrading, I’d highly recommend that route.
MineOS 0.6.x does not have any special requirements, though it does make some pretty drastic changes in its architecture. For example, instead of using an existing webserver and CGI, 0.6.x uses Cherrypy Webserver and runs in the background as a daemon.
So let me try to address each of your issues separately:
Upgrading to 0.6.x
Definitely doable. MineOS requires a number of dependencies not included in your install, such as git, python2-cherrypy. The one thing about upgrading to 0.6.x, however, is it will require you to remove the existing web-ui as well. And doing so may cause disruption to your production server (no, it will cause disruption). So you’ll either want to do this after you:
a) make a snapshot and accept server downtime
b) do this in a separate VM.
Arch Linux is actually based off of Crux (if nothing else, at least on the philosophy). That makes the instructions for installing MineOS-on-Arch the most useful starting off point. The one difference is that Crux doesn’t use pacman (first step); other steps should be okay to use as-is.
That said, the Crux I distributed years ago was 2.7 I think. That makes your version rather outdated. There might be good reasons to consider using a more updated version, but as is the philosophy with Crux…that will require a LOT of work you’re probably not interested in. That might be one reason you could consider just exporting your worlds rather than keeping it.
Update your minecraft versions
Minecraft server jars are drop-in replacements for eachother. I’ll be honest with you; I don’t even remember 0.5.x that well anymore with all the time and efforts put into 0.6.x (maybe close to 2 years ago). wget-ing an updated server jar and replacing your existing one should be all it takes to update minecraft. The issue, however, is whether or not 0.5.x is even capable of handling the new Minecraft ping protocol (which I suspect it will not). Thus, there is probably a hard-cap of what version the web-ui will work with, making that a bit more inconvenient.
In all likelihood, Crux ports have been updated to address shellshock. It would make sense, with the recent updates to the ports in git.
In any case, you’d have to go and rebuild it (or download the packaged binaries). It may not be a pleasant experience if you haven’t updated packages for a few years, as there will be a lot of dependency catch-up; this would make even updating a separate VM very tedious.
It’s certainly not impossible, and I’m certain it would work, but the amount of labor required to do so is likely bordering ten times as much as installing a new distro. If you’re interested in pursuing this all the same, let me know and I’ll try to provide more detailed descriptions.