Apple will release an upgraded version of AirPods in the second half of 2018, according to KGI Securities analyst Ming-Chi Kuo.

Media reports over the past few days on brisk AirPods demand and Apple struggling to keep up with holiday season demand align with our findings and positive predictions on AirPods in several previous reports. […] In 2018, we predict AirPods shipments will grow 100% YoY to 26-28mn units. We forecast the ASP of RFPCB for upgraded AirPods in 2H18 may increase, further benefiting business momentum of Unitech and Compeq.

An excerpt from Kuo's latest research note, a copy of which was obtained by MacRumors:

Kuo said one internal change on the second-generation AirPods will include a "smaller quartz component," but he didn't provide any further details about new outward-facing features or improvements to expect.

Kuo said the new AirPods will continue to be assembled by Taiwanese manufacturer Inventec, with individual components supplied by fellow Taiwanese companies such as Unitech, Compeq, TXC, and HLJ.

Apple will also be releasing a new inductive AirPods charging case that will enable the wireless earphones to be charged with its new AirPower charging mat, which it said launches at some point in 2018.

Apple teased the AirPower mat at its iPhone X event back in September. It will be able to charge the Apple Watch Series 3, an iPhone X or iPhone 8 model, and AirPods inside the new charging case simultaneously.

As for the current AirPods, Kuo said Apple's suppliers are unable to make them quick enough to fully satisfy what he believes is robust holiday season demand, which likely explains why AirPods are sold out until January

Kuo, who keeps a close eye on Apple's supply chain in Asia, said Apple has recruited Luxshare to help make AirPods, but RF printed-circuit boards for AirPods batteries are proving to be a key production bottleneck.

Kuo also reiterated his estimate that AirPods shipments will double in 2018 to 26-28 million units on a year-over-year basis, suggesting Apple will have sold around 13-14 million AirPods worldwide by the end of this year.