Similarly, you can't always expect any 2.6 kernel to be a drop in replacement for a 2.4, 2.2, or 1.x. You *can* expect a 2.6.y kernel to be virtually a drop in replacement for 2.6.x where y>x though. See what I'm getting at?
No announcement yet.
Linux 3.0 Kernel May Remove Some Old Cruft