Five days before its official launch, the Xiaomi Mi Band 4 made a surprise appearance on Aliexpress. The latest Xiaomi smart band is available for pre-order in its non-NFC configuration for $49.99. The shipping is not taking place for at least 25-days, but the listing still gave us images and specs of the band in addition to the pricing. Mi Band 4 in hand The fourth iteration in the Mi Band series will come with a 0.78-inch color display with a 240x120 resolution. The overall shape will remain identical to its predecessor but the battery will get a bump up to 135 mAh to make up...