It appears that the negotiations between Gretech and KeSPA have broken down for good. On October 11th, Gretech warned KeSPA not to proceed with any tournaments before an agreement was reached, but KeSPA went ahead and officially announced the new Proleague season on the 13th. In response, Gretech has stated "There will be no further negotiations."
Regarding the situation, KeSPA stated "It was not proper etiquette for Gretech to send us a final notice only days before our scheduled opening day. Many players and fans are awaiting the Proleague, and we cannot push back its start. We will continue to try and negotiate afterwards."
On the other hand, Gretech solidified its stance to cease negotiations with KeSPA, stating irreconcilable differences.
At this point, legal action seems inevitable.