After six years of negotiations, Apple and China Mobile, which is the world's largest wireless carrier with 760 million subscribers, announced a long-anticipated agreement on Monday, Dec. 23.

China Mobile was the only Chinese carrier not to offer customers the iPhone up to now due to compatibility issues with the carrier's 3G wireless technology, known as TD-SCDMA. The disagreements over details, such as revenue sharing, delayed the deal between the two giants.

The latest deal will most certainly help to boost iPhone sales with a bigger network and state-owned China Mobile's marketing power, adding billions of dollars to its revenue, and the Cupertino-based tech company now has access to all carriers in the world's biggest handset market.

The iPhone 5S and 5C are slated to go on sale in Apple and China Mobile retail stores beginning on Friday, Jan. 17. China Mobile customers can register orders for iPhones staring on Christmas Day. Pricing details and financial terms of the agreement will be disclosed at a later date.

The deal comes a month before China's Lunar New Year holiday in late January, which is a big gift-buying season. This "will provide an immediate boost to Apple's share in China," said analyst Nicole Peng of Canalys, a research firm.

Sales predictions of iPhones under a deal with China Mobile vary widely, from 10 million to 40 million. A key issue is whether it leads to additional sales or only prompts existing users to switch to China Mobile.

The Apple CEO Tim Cook told the official Xinhua News Agency in January that he expects China to surpass the United States as its biggest market. About 50 million iPhones have been sold in China in the past two-and-a-half years, according to analyst estimates.