Sprint’s Samsung Galaxy Mega and S4 Mini phones will be updated over the air with the VoIP app first, with other devices to follow, according to a low-key ‘via blog’ announcement from the company. It will be interesting to see how much marketing push Sprint applies when the time is right.

The move may even bear the fingerprints of Sprint boss, Masayoshi Son, who told Mobile World Congress in 2008 that one of the keys to his success with Softbank’s broadband service was to offer free VoIP. “One hundred per cent” of his users had free voice over IP for calls between them he said - so he’s clearly a big fan of free VoIP applied in the right place (see - Newsdesk: New from Mobile World Congress..).

To now, telco WiFi VoIP, where it exists, has usually been carefully segregated from the main switched voice services. Sprint’s VoIP looks as though it will, to all intents and purposes, be a transparent addition, using the same number with all calls and texts free, except international, so there’s even an incentive to use it instead of cell service if the user is on a minutes bucket.

As Sprint points out, the primary motive for the service is to compensate for bad coverage in the home, especially where “building materials are interfering with the Sprint network”, but users will also be able to use it at hotspots to both make and recieve calls when out of Sprint’s coverage area.

The move also part-solves the international roaming issue since users can call home for free via WiFi when abroad.