This might be a SCAM though, according to the comments under the GoodEReader article and comments on reddit.
It appears "Reinkstone"
belongs to Wiwood Technology, who also created the "E-Pad". The E-Pad had a very dodgy history. It was released three times (first as Whisky E-pad, then Eewrite E-Pad and finally as Wiwood E-Pad), during multiple Kickstarter campains. Apparently these guys quickly disappear and abandon their product after they have got your money. Then they reappear later under a different company name or label.
So there is a high chance these "software issues" mentioned by GoodEreader might not be worked out after all. (They have only registered the "ReInkstone" label for 1 year, expiring at the end of November.)
More likely you can buy the updated version next year again under a different name.