GroupWise 6 migration and upgrade

It seems I can't put this off any longer and I suspect I have a lot of work ahead of me. Here's my situation:

I have an old NetWare 6 SP4 server. The time to have retired this server has long passed. The hardware is the same vintage as the software and I don't think it can withstand an upgrade. All that is left running on this box is GroupWise 6 SP4.

I have a newer server running SLES11 SP4 Xen. I have an OES2015 VM which is to be the home for my new GroupWise. My plan is to move to GroupWise 2014 R2.

This is my GroupWise 6:

  • Single domain and PO
  • 5 users
  • PO size: 7.5 GB; 120 K files

My GroupWise 6 recently encountered an issue described here. I know I should have a healthy installation before attempting an upgrade but I'm running out of options.

What are my migration options? I expect GroupWise 8 to be part of the migration process, is it not? I'm quite happy to refer to the documentation for all the gory details.