No, it's not the Treo 750 ROM Update we just asked for a minute ago. Neither, sadly, is it Windows Mobile 6, which I think we need to give up hope on seeing on the 700wx in any flavor. Neither, sadly, is it the pulled ROM for the Verizon 700w|wx. No, instead it's a simple update for the Sprint 700wx that we'd seen previously for the Verizon version. It's still good news, though, as it adds some great features:

High-speed dial up networking (DUN) – use your Treo smartphone as a wireless modem for fast web access virtually anywhere1. Supports USB and Bluetooth connections.

Advanced audio support (A2DP) – enjoy your music in full stereo with new support for Bluetooth stereo headsets.

Hands-free enhancements – Drive safely and work more efficiently. Get support for even more Bluetooth carkits and the Palm wired carkit.

Read: Palm - Support

Inexplicably, it still doesn't have threaded text built in. We know the hack to added threaded SMS on the Treo 700wx works and works well. Ah well, I guess you'll just have to reapply that one.