A woman uses Uber Technologies Inc's car-hailing service via an electronic screen in Tianjin.[Provided to China Daily]

BEIJING - Uber China will launch a major upgrade to its mobile application and expand into 400 cities in China by the end of this year, the company has announced.

Uber China and DiDi said Tuesday night in a joint announcement that the upgrade is "the beginning of a renewed quest for product innovation across the two services."

The top two ride-hailing companies in China closed the merger deal on Aug 2.

The upgrade will enable "back-end integration" between Uber China and DiDi Chuxing.

The upgraded app will maintain Uber China's popular settings, including its simple user interface and 24-hour in-app customer service, and introduce elements of DiDi's highly successful local design.

Uber China and DiDi vowed to synchronize ride dispatches to qualified DiDi and Uber China drivers and bring positive results in efficiency, said the joint statement.

Prior to the merger, both companies competed in granting subsidies to users to grab market share, which led to financial pressures.

Since the merger, users have complained of higher costs on the two rideshare services, and the Ministry of Commerce (MOC) is investigating the transaction over monopoly concerns.

MOC spokesperson Shen Danyang said in September that Uber China and Didi did not notify the ministry before signing the merger deal, as required by the Anti-Monopoly Law and other regulations.

DiDi, as the world's leading comprehensive one-stop mobile transportation platform, now offers a full range of mobile tech-based mobility options for some 300 million users across more than 400 Chinese cities.