According to what I've understood from the last Nitro update...
THE NEXT ZEROSUM WILL HAVE THE LAST SAIYUKI RELOAD CHAPTER!???
After Saiyuki Reload will start a new serie, the last one, who probably will be called only "Saiyuki".
Since Saiyuki Gaiden is finished, the new serie will explain the points not analyzed that connect the main Saiyuki with Gaiden.
Obviously I'm not sure at 100% and if someone is able to understand more...let me know, please!
The cutted illustration showed on Nitroblog is from the poster selled together with the ZeroSum magazine published today in Japan.
I don't know if there is a Saiyuki chapter in this magazine or not.