Actually, the email (which arose from retailer EB Games) is even more vague: "The latest information from Warner is that the updates won't be available until Spring. Due to this we have made the difficult decision to recall all PC stock from stores to return to the vendor until an acceptable solution is released."
"Spring" meaning the Australian spring, of course, which is fall for the northern hemisphere.
It sounds like you can essentially expect Arkham Knight to be fixed by the end of the year, though whether that does in fact mean two months from now in September or five months from now in December is anyone's guess. The fact EB Games is returning all PC copies of Arkham Knight to WB is not a great sign.
Either way, what a mess. I can't believe I'm saying this but...maybe you should look at buying a console copy of this one Or maybe just don't bother playing it at all.