Upgrade of both Bonita (6.4.1) and server OS (Ubuntu 14.04)

Q&A
1

Hallo everybody.
I need to upgrade a Bonita 6.4.1 installed on an old 14.04 Ubuntu server. I would like to get some advice on what would be the best way to do it.
I think my options are:

  1. Upgrade the OS to 16.04 and then to 18.04 (all LTS) and then run the migration tools of Bonita;
  2. Migrate all the Bonita sw/settings to a newly installed 18.04 Ubuntu server and then upgrade Bonita with the migration tools;
  3. Install a new 18.04 Ubuntu server from scratch, install a new ‘empty’ Bonita software at the latest version and, at last, import data/settings from the old instance (if it’s possible at all).
    All three ways seem subject to many possible criticalities, and I’m not a real system manager (nor an expert of Bonita or JBoss).
    What should I consider in order to take a decision?
    I have a test environment available, in order to test the process before doing it in the production system.
    Thank you all for your help,
    Emanuele
2

I ended up with the first option I suggested in the original post.
I tried to install Bonita v. 6.4 on a freshly installed Ubuntu 18.04 server, but there were compatibility issues with some libraries. So I surrendered and started from the original machine, upgrading first the OS from Ubuntu 14 to Ubuntu 16, than launching the migration kits for Bonita (the one for the migration 6.4->7.0 and the second for 7.0->7.7.4).
At that point, following the instructions, everything went well, except for some OS related changes. The only aspect I find useful to bring to attention, is that, by default, Bonita 7.7 requires openjdk 8, while Ubuntu 18 suggests openjdk 11 and you need to add apt repository universe, in order to install v. 8 (then you need to choose the right default version through update-alternatives command).