When Singapore pulls the plug on its 2G mobile phone network this year, thousands of people could be stuck without a signal - digital have-nots left behind by the relentless march of technology.

From technophobic pensioners to cash-strapped migrant workers, some 140,000 people in highly-wired Singapore still use the city-state's second generation (2G) network and cheap, robust handsets.

First rolled out in 1994 - when playing Snake was the pinnacle of mobile entertainment - 2G has long been superseded technologically, with new gold standard 5G offering lightning fast connectivity for a generation used to streaming movies and TV directly to phones.