Since I tend to forget things the day after I do them, I've decided I'm going to write this one down. While I can manage my way around a LINUX install, especially Ubuntu flavors of Linux, I'm no system administrator or whiz kid by any stretch of the imagination. I tend to plunk around and can find some articles online (usually on Ask Ubuntu forums) to get done what I need. Rather than forget where I found this info, this time I decided I'm going to write it up. The 5.1.2 upgrade to CrashPlan Pro requires Oracle Java 8 as indicated in this article. Since I run all of my Ubuntu boxes headless (they're all VMs) I do everything the way any good UNIX head does: via the terminal. Of course, as I stated above, I'm no super user in LINUX so I take the easy way out and use package managers to do the installation, apt-get in particular since I am on Ubuntu. Unfortunately, apt does not have Oracle Java 8 as an available package. So in order for me to be able to use apt-get, I needed to first find a repository that had it.
A quick Google search led me to this article. After following the steps in the article, I had Java 8 installed and ready for the upgrade to version 5.1.2 of CrashPlan.
The next step was to make sure I had a fresh database dump from CrashPlan. Into the GUI for the CPP server to generate a dump. It's a good idea to copy that dump file off to another server/system.
Now that we've backed up and we have Java installed, go ahead and download the update files. You can find the files, along with the official CrashPlan documentation here.
Finally, once you have the server upgraded, you'll want to upgrade your client devices. You can find the official documentation here.