It's a given that HTC will eventually launch its new Butterfly S in China, but will it be a dual-SIM version like the One Dual variants offered over there? The answer is yes, according to a filing in TENAA's database. This particular SKU comes with WCDMA radio, meaning it'll be picked up by China Unicom but will also work in many parts of the world.
According to a source of ours, the entire back cover (black or white; with NFC antenna) is removable to give access to the two micro-SIM card slots, as well as a microSD slot as featured on the One Dual. The trade-off, however, is the increased 10.89mm thickness from the original 10.6mm. That said, the listed 158g weight is a little below the original 160g, so we're not sure if the battery capacity is still at 3,200mAh.
The rest of the phone should otherwise be identical to its single-SIM sibling: 1.9GHz quad-core processor (so should be the same Snapdragon 600 SoC), 5-inch 1080p LCD, UltraPixel main camera, BoomSound stereo speakers and Android 4.2.2. As always, we shall keep an eye out for a price and date.