As far as I know the DS4 still uses the Bluetooth 2.1 protocol.
There have been A LOT of Bluetooth improvements over the last years. Bluetooth 4.0 - 4.2 only drain a fraction of power, which should improve battery life. For Bluetooth 5 there will be improvements in all areas (power drain, range, speed): http://www.techradar.com/news/networking/bluetooth-5-everything-you-need-to-know-1323060
I really hope that the new DS4-model (transmitter) and the PS Neo (receiver) both support Bluetooth 5 or at least 4.2: https://en.wikipedia.org/wiki/Bluetooth#Bluetooth_v5
P.S.: Damn, according to the FCC document, it it still Bluetooth 2.1 + EDR? WTF? That is still tech from 2007, which was already a shame when the PS4 released in 2013! Bluetooth 4.0 (aka Bluetooth low energy) is available since 2010: https://en.wikipedia.org/wiki/Bluetooth#Bluetooth_v4.0
I hope that this is only an enhanced model for PS4 and that the Neo gets a "DS4.5" with newer bluetooth specs.
Yes, it's a shame to keep using such outdated bluetooth technology. 2.1+EDR (Enhanced Data Rate) is nasty old crusty tech.
I'm not sure Bluetooth 4.0 or higher really provides any necessary feature(s), PLUS it would make the "DS4.5" incompatible with current PS4s (I don't know how backwards compaitible Bluetooth 4.x+ is with the 2.1+EDR receiver in the OG PS4.
Back when the DS4 was announced, Mark Cerny (I think) was asked about the decision to stick with BT 2.1+EDR and he said that for what the DS4 needed to do, BT 2.1+EDR was more than adequate. So maybe there just isn't a valid reason to move to a later version of the spec? Blutooth already is a very low (battery) power tech, so a small increase in the battery capacity would far outweigh any power savings advantage of BT 2.1 vs 4.x
What I'd like to see are contact charger points built into the controller, on either side of the USB port. That way you could chge via USB port, -OR- use a contact charger without having to stick a little adapter into the USB port.