It's been a little while since Motorola has launched a new phone, but there has been some recent documentation that was discovered at the FCC which looks like they may be working on a possible new flagship device that supports multiple LTE bands as well as a few GSM bands. The FCC ID IHDT56UC2 listing merely describes this device as a mobile cellular phone from Motorola with model name 5137. That doesn't give much to go on but there are a number of other details to be picked out which at least give some insight as to what Motorola has planned for this device. Besides supporting LTE bands 2, 4, 5, 7, 12, 17, 25, and 41, and GSM bands 2, 4, and 5, the phone also supports Qualcomm's quick charge 2.0 technology and from corner to corner the device measures in just a little bit bigger than the Motorola DROID Turbo.
From the Quick Charge support it's easy to gather that this upcoming/unknown Motorola phone will be able to charge up rather fast, but it should also be capable of fast downloads as it seems the FCC tested it for MIMO WiFi and LTE-Advanced technologies. That particular detail along with the fact that it was tested with a Motorola Turbo Charger suggests the new device will be powered by a Qualcomm chip, very likely one of the new processors which has been seen in a couple of other OEM flagship phones so far this year, possibly the Snapdragon 808 or the Snapdragon 810.
In addition to supporting multiple LTE bands from both T-Mobile and AT&T as well as Sprint, the device appears to support Bluetooth 4.0 LE and NFC. The FCC documents also lists details about the battery of the device, although only briefly, listing it as model name FX30. Unfortunately, there is no mention of the battery capacity at this time which is to be expected given the lack of detail about the rest of the device. Given its size though and support for potentially multiple networks, Turbo Charging, and LTE-A, it'not likely to be a low-end to mid-range device, which is where the speculation about it being a possible new flagship comes from.