<p>(Reuters) - Apple Inc is exploring launching iPhones with bigger screens, as well as cheaper models in a range of colors, over the next year, said four people with knowledge of the matter, as it takes a cue from rival Samsung Electronics.</p><p>The moves, which are still under discussion, underscore how the California-based firm that once ruled the smartphone market is increasingly under threat from its aggressive South Korean competitor. Samsung has overtaken Apple in market share through the popularity of its bigger-screen Galaxy "phablets" and by flooding the market with a range of products at different prices.</p><p>Apple is looking at introducing at least two bigger iPhones next year - one with a 4.7-inch screen and one with a 5.7-inch screen - said the sources, including those in the supply chain in Asia. They said suppliers have been approached with plans for the larger screens, but noted it is still unclear whether Apple will actually launch its flagship product in the larger sizes.</p><p>"They constantly change product specifications almost to the final moment, so you're not really sure whether this is the final prototype," said one person with direct knowledge of the matter.</p><p><a href="http://www.reuters.com/article/2013/06/13/us-apple-iphone-idUSBRE95C05Q20130613">Keep reading...</a></p>