There will be two million iPhone 3GS units produced in the quarter ending December 2011, despite the handset now being more than two years old, it has been claimed.

Digitimes reports that OEM production of the iPhone 3GS remains steady and that between 1.4 million and 1.6 million units will be produced in the first quarter of 2012, according to its sources in Apple's supply chain.

Part of the reason for the high demand for the iPhone 3GS is that it was the first iPhone to be available free on a contract in the US through AT&T, though the network operator now charges a nominal $0.99 for the handset.

In the UK, it is free on contracts offered by most operators, beginning at £20 per month from Orange and Three, £15 per month from T-Mobile, £30 per month from Vodafone and from £18.50 per month on O2. If you want to buy it SIM-free from Apple, though, it'll cost you £319.

Apple 'will sell 30 million iPhones in Q4 2011'

Production of the CDMA version of the iPhone 4 is expected to reach between 800,000 to one million units in the fourth quarter of 2011 and 500,000 to 600,000 units in the first quarter of 2012, the report added.