The wearable-electronics market shows no signs of slowing down, with research firm IDC estimating its year-over-year growth at 126 percent in the fourth quarter of 2015. On a per-unit basis, that means wearables manufacturers shipped 27.4 million units during the quarter, a healthy fraction of the 78.1 million units that IDC estimates shipped overall in 2015. “Wearables can exist and are welcome in the mass market,” Ramon Llamas, a research manager for IDC, wrote in a statement accompanying the data. “And since wearables have yet to fully penetrate the mass market, there is still plenty of room for growth in multiple vectors” including new vendors and form-factors. In IDC’s estimation, Fitbit continues to rule the category, having shipped 8.1 million units in the fourth quarter, followed by Apple with 4.1 million units and Xiaomi with 2.7 million units. IDC believes that the Apple Watch’s shipment volumes grew only slightly between the third and fourth quarters, and wonders openly whether a second-generation watch will add features that will make the device more of a breakaway hit. But if current rumors prove correct, anyone hoping for a radically retooled Apple Watch may end up disappointed: according to 9to5Mac and other Apple-centric blogs, basing their information off the ever-popular unnamed sources, the next version of the smartwatch won’t prove radically different from version 1.0. Tech pundits (and rival manufacturers) will also keep an eye on Xiaomi, which sells inexpensive fitness trackers to the Chinese market, but has made no secret of its ultimate intention to become a more international brand. For developers interested in the wearable-electronics category, the message conveyed by IDC’s latest data is pretty clear: appetite for smartwatches and other wearables continues to rise, with a corresponding need for apps and services. But the big question is whether 2016 will see a radical reshuffling of the current brands’ rankings, or if Fitbit and Apple will remain on top.