In short: OpenGL 1.x will still be supported.
It's theoretically possible for someone to write an OpenGL implementation that only supports 3.x and up, but supporting the older stuff gives you such a wide range of existing applications that it would be silly not to support it.
Some parts of the OpenGL 1.x pipeline may be implemented in a non-optimal (i.e. slow) manner, but things will still work. ATI drivers made picking horribly slow at some point, prompting changes in Blender, for instance.
On the OpenGL ES side things are a bit more complicated. I'm not aware of any instances of it, but ES 2.0 and onwards are so much different from ES 1.x that it's possible that some devices have no ES 1.x support. In most cases, ES2+ hardware emulated ES 1.x in software (generating shaders on the fly and fun things like that).