Probably in November. They are probably going to have a Superday 2(Superday 1 was last week) with the release of Adventures of Superman season 5/6, Superman TAS Vol 3, Superboy Season 2 and the Ultimate 14 disc Superman Movie Collection
all sounds about right except Superman TAS Vol. 3 came out this past week so that is now complete. I really hope we do see Superboy: Season 2 because I blind bought season 1... and while not the greatest... I am really enjoying it.
Perhaps in lieu of an animated Superman release, they could substitute the Superman serials for it.
One thing I'm wondering is if they'll do anything rebarding the final episode which had the series end in a cliffhanger. It would be nice if they could have an interview with the producers and/or Dean Cain to explain where they would've gone with that. I guess we'll ever get Teri Hatcher to do an audio commentary on this series. Ah well...
I just got an email back from WB on July 4 (as I was hanging in the New Krypton Arc and wrote the source). The email said there was no production information available on that request. I've only found two sources online. One looks like it might be a pirated download (I'd rather have the real thing) and one is a set of transcripts for educational purposes. I hope your right about the fall release.