Microsoft has been asking its Messenger clients to switch to Skype since last November. (Microsoft)

Microsoft is informing its users that it will start the process of switching off its Windows Live Messenger service on March 15.

The company announced last November it would be dumping its service in early 2013 but gave no firm date.  It encouraged Messenger users to download Skype and begin using that service instead. Users of both services are able to merge their accounts and contact list

The switch comes in the wake of Microsoft’s acquisition of the popular VoIP service last spring.

Windows LiveMessenger launched in 1999 with a text-messaging system. Eventually, it added photo delivery, video calls and games.

In November, the announcement said Messenger will be retired in all countries in the first quarter of 2013, except in mainland China, where it will still be available.

There is a glitch in terms of complete stoppage of service  — Microsoft's own Windows Phone and Xbox devices use the Messenger service.

Windows Phone incorporates Messenger chat into its messaging hub, but can't communicate with the Skype network at all. The Xbox, using ChatPad and Kinect video chat, is integrated with Messenger.

On March 15, the Windows Messenger client will be unable to connect to the network and users will be informed that they must install the Skype client instead. The Skype client will continue to connect to the Messenger network and permit communication with Messenger users.

Meanwhile, those using Windows Phone and the Xbox will still, apparently, be able to use their chat devices.

Worldwide, Messenger has about 100 million users, while Skype boasts about 663 million who make voice and video calls over the internet. The amount of calling on Skype's network totalled 207 billion minutes last year, according to regulatory documents.

Skype is supported on all platforms, including Android tablets and iPad, video well, as calling landlines and mobile phones. An average of about 8.8 million customers per month pay to use Skype services.

Skype users can also share screens, and video call with friends on Facebook in addition to making group video calls.