Motorola are working on the third generation of Moto G and it is not believed to be a major update on the current Moto G (2014). The third generation of Moto G will have 4G LTE support and also support Dual SIM.
Most of the specs of the Moto G third generation will be same as the current one. It has a 5in display with 720×1280 pixels resolution; enclosed within Gorilla Glass 3. It will be powered by a 1.2GHz quad-core Qualcomm Snapdragon 400 processor and 1 GB of RAM.
The new Moto G will have 16GB internal storage with support for external storage. The connectivity option will be 4G LTE, Bluetooth 4.0, Wi-Fi and micro USB connectivity. The new Moto G will have a slightly better 2390 mAh battery.
Dual SIM support will not be available for all the regions. Other details such as pricing and release date are not available yet.