You can sideload it. The link is
here.
You want this one:
Mark 4 Hardware: Aura HD/Glo and TouchLC (Low Cost -N905C Model).
90.5 MB - 92,698 KB - 94,922,390 bytes
Make sure when you do it that you unzip the file, and drop the three files that you unzipped into the .kobo file (dot kobo). You can have a lot of fun (NOT) if you drop it in the root directory by mistake. (Yes, me).
Or you can wait til it rolls out to you from Kobo. That would require you to connect wifi periodically and hope it's your turn.