To our knowledge, none of the previous generations of any Echo speaker is entirely obsolete, they just don't have all the features--or the audio performance--of the latest models. So, buying a previous-generation device is a great way to save a lot of money. That said, the Echo Dot, Echo Dot with Clock, and Echo Dot Kids Edition (5th Gen) are the latest versions of Amazon's smallest Echo speakers; the Echo (4th Gen) is the latest version of its larger sibling; the Echo Show and Echo Show Kids Edition (2nd Gen) are the latest versions of Amazon's 5-inch smart display; the Echo Auto (2nd Gen) is the latest model of Echo designed for in-car installation; and the Echo Show 10 (3rd Gen) is the latest--and so far only--model to have a motorized touchscreen. These Echo models are all first-generation products and have not been superseded: The Echo Show 15, Echo Studio, and Echo Sub.