Earlier today, iFixit posted up their teardown walkthrough of the Pebble smartwatch, and noted that the device didn't support Bluetooth 4.0 -- only Bluetooth 2.1. However, there seemed to be some confusion between the specific chips used in the watch, as Pebble has responded to the teardown, saying that Bluetooth 4.0 is indeed supported.
The confusion seems to be warranted, though, as Pebble notes that while the chip used in the Pebble smartwatch doesn't normally support Bluetooth 4.0, the company had the firmware of a different chip flashed on the ones used in the watch in order to support Bluetooth 4.0. The situation is definitely a little confusing, but Pebble says that this was done to speed up orders.
Pebble posted on Reddit the details of the situation, and note that the Pebble features a PAN1316 chip from Panasonic that uses Texas Instruments components. The chips that TI sent to Panasonic were labeled CC2560, which doesn't support Bluetooth 4.0. However, Pebble had Panasonic simply flash the firmware of a CC2564 in order to get the latest Bluetooth support.
However, while the smartwatch does, in fact, come with Bluetooth 4.0 support, Pebble hasn't yet switched it on in the watch's operating system, but it seems they'll be doing that sometime in the future, most likely with an update. It's unclear why they're holding back 4.0 support, but it could be a number of reasons at this point.