So most importantly, and I'm sorry you hit this, there's no 'upgrade' (in the classic sense of the word) process for 6.x to 8.0. A mobility manager (MM) is required in MOST cases as the intent is that the MM manages every config element of the locals (d of the local's IP). You CAN run a single controller in stand-alone mode with 8.0 but as stated before, there's no 'upgrade' path.
We have some migration tools that HPE Aruba's TMEs (like myself) are scrambling to get a feel for and get documentation out to the field and partners/customers ASAP, but it's going to take time as the final tool was only released a few weeks ago and it requires some time for us to get a handle on it to get it documented.
For now, since 8.0 is accessible, I would engage your local account team for help (though be aware they may be as new to it as you are). 8.0 is a pretty big tectonic shift in how the controllers are managed, so it's best to be done in a lab environment with controllers NOT in production until we can get more field digestible information out.
Our target is officially Sept 1 to have everything done on our list, but we are prioritizing the early aspects (MM install and config, migration process, etc) and we will be releasing that to the Aruba SEs and partners as soon as they are completed. For me, I will be spending most of Thursday getting the migration tool run through it's paces and hope to have some collateral by next week. I also will be doing the installation instructional videos and PPTs as well (which I have already done but have to re-record as engineering made some last minute process changes that I have to account for).
So please be patient, this was a bit of a Ready-Fire-Aim release in that engineering got it out to get some field soak in to it, but our TME and field is pretty much seeing it in it's final form at the same time as our customer base :) It's awesome stuff! Just very, very new. Thanks for your patience