Correct, the "blue" Series III mixers are discontinued and replaced by a range of "black" mixers, which are 64S, 32S, 32SX (SL 24) and 32SC (SL 16). PreSonus has published a "StudioLive Series III S Comparison Guide" for the new mixers, which you can find here: www.presonus.com/products/StudioLive-32SX/downloads.
The 32SX and 32SC do NOT have BlueTooth, and they do not have scribble strips for Fat Channel and DAW control. Otherwise they are technically identical with SL 24 and SL 16. Even if the figures 24 and 16 do not say it, both mixers are 32 channel mixers. The "black" models now express that in their name.
The 64S is a quad-core mixer with 64 input channels, 32 flex mixes and 8 FX. All blue and black mixer use the same firmware. Chorus and Flanger are the latest additions to the firmware.