It seems like Onion only partly discontinued the Rocki expansion. I've gone through Onion's blog. Shipping of the Rocki expansion is still mentioned in the Kickstarter and Indiegogo updates on February 22 and 24 (https://onion.io/blog-kickstarter-update-february-22-2017/). About two weeks later, in the Kickstarter update on March 6, it is listed as no longer available due to manufacturing difficulties. Nothing is said in that particular update about the Rocki expansions that were actually shipped. But in the Kickstarter and Indiegogo updates on march 8, they repeat that it is no longer available. But they also add, "This applies to backers who have not yet completed the survey. If you have already completed your survey and ordered these items, you will be getting them!". And that's the last mentioning of the Rocki expansion in Onion's blog. So, of course I am hoping for some kind of documentation.

@Douglas-Kryder Thank you. That did help some. So the card is developed by Rocki. I tried finding information at Rocki's website (myrocki.com). No luck there. To continue this, I emailed support@myrocki.com a week ago, asking where I can find documentation. No answer so far... If I do get an answer, I will relay that here.

With my Omega2+ I got a bunch of extra goodies, among which is a sound card expansion, labeled ODS-SOUND-V1.1. I find no information about this in the Omega2 documentation. My google karma is not good enough to find anything that way. Does anyone know where I can find information about this card?