Not sure if this has been posted already, but just in case…
Thank you for posting.
It’s funny, when they say they aren’t sure what era is showing, I wonder if they happened to look at their own photo.
There was actually a version leaked at NYCC a few weeks ago. Apparently it was not supposed to be leaked but somebody(Didio) leaked a blurred version of it. Bleeding Cool and other websites were able to decipher it. Among the retcons the most changes seem to have been made in the Golden Age or generation 1 period.
Wonder Woman now becomes the first hero of the Golden Age in 1938 and apparently inspires and eventually helps form the JSA. Dan Garrett is active in 1940 as the Blue Beetle and Black Canary Dinah Drake is now active as early as 1942.
Several days later Bleeding Cool reported that DC was surprised that so much of the timeline had been revealed and warned that many of the events were only tentative as DC was still tweaking and finalizing the timeline and might even do more tweaks after gauging fan reaction