This is something you should strictly file under rumors that have little chance of turning out to be right, but according to the Korean media, who cite sources inside Samsung, the Galaxy S5 will be officially announced in January next year. The reason? Well, it's apparently the disappointing sales of the Galaxy S4, so Samsung is hoping to get the next flagship out earlier than usual, supposedly in February.
The Galaxy S5 is expected to be the first Samsung flagship to sport a metal construction instead of a plastic one, and also debut Samsung's 64-bit Exynos processor with simultaneous eight-core processing and a high-end 16-megapixel camera with optical image stabilization and improved low-light photography. As has been the tradition since the Galaxy Note II, it will likely run on Android 4.4 out of the box.
Again, none of this is confirmed, so take everything with a giant pinch of salt. Launching a flagship less than a year after the previous one, and especially just a few months after the Galaxy Note 3, doesn't seem like the brightest thing to do, but we'll just have to wait and see what Samsung is planning.