Microsoft CEO Steve Ballmer (L) shakes hands with Skype CEO Tony Bates during a news conference on May 10, 2011 in San Francisco, California. Microsoft bought Skype for $8.5 billion. (Justin Sullivan/GETTY IMAGES)

Skype is officially replacing Windows Messenger Live as the chat program of choice on the Windows platform, the company announced Tuesday. Users will be able to transfer their contacts for instant messaging and video chat to Skype.

Messenger will be retired everywhere in the world, except for mainland China, by 2013. CNET reported that, in China, Skype and Messenger are both joint ventures with Chinese companies, making a merger logistically difficult.

For everyone else, Skype said, the process for transferring contacts is as simple as signing into the latest version of the program with a Microsoft account.

Users will be able to merge Skype and Messenger accounts if they wish.

Skype, which announced it would be acquired by Microsoft in 2011, highlighted a few key features that Messenger users can expect. In addition to support on more devices — including the iPad and Android tablets — Skype said Messenger users will be able to instant message, call landlines and cellphones, share screens, place video calls on mobile phones, place video calls with Facebook friends and use group video calling.

Windows Live Messenger has lost 45 percent of its customer base in the past year, the BBC reported, with Skype making gains in the instant messaging space.