Moto X4 is an Android smartphone developed by Motorola Mobility, a subsidiary of Lenovo. Unveiled on August 31, 2017, at IFA, it is a revival of the previously discontinued Moto X line. It was released in Europe at the end of September 2017. In the United States, an Android One version of the device was also released, marking the first device to be released in the US as part of the Android One program. In 2018, Motorola launched the Motorola One lineup as upper mid-range replacements for the Moto X4.