HWE kernel: http://askubuntu.com/a/248936

Here is HWE, https://wiki.ubuntu.com/Kernel/LTSEnablementStack and there was a change recently in the policy.

In a nutshell,

1. if you are happy with the currently kernel in Ubuntu 16.04, then you can stay with this kernel (it's version 4.4) and it gets supported until 2021).

2. if you want to jump to the new supported and tested (tested in 16.10) 4.8 Linux kernel, then there is a command described in https://wiki.ubuntu.com/Kernel/LTSEnablementStack that helps you upgrade. However, when you upgrade the kernel (and Xserver stack that are linked together), your Linux kernel will be upgraded every six months from now on, until 2021. The next kernel version update will be in July, and it will be whatever Linux kernel was released in Ubuntu 17.04.

Does that means you can have fairly recent kernels with LTS releases? If so, amazing. That was my biggest complaint of Ubuntu on servers.

This is the first time I'm hearing about this, but the link would suggest that yes, this is what it means. Kind of a sidethought, but I wonder if I can get an easily-administrable WRT distribution (like Tomato is) on my DSL router that has the kernel's bufferbloat fixes.

What do you mean by standard feature? HWE kernels were already introduced after each Ubuntu release.

Ubuntu used to add a kernel to the LTS from each subsequent release, but they were separate packages. Now there will be just one HWE package that will roll until the subsequent LTS.

Unfortunately, Alternate release images are not published after 16.04.1.

Everything in 16.04.1 comes from the package archives. It's what you get by default from a particular image that changes. You can still get to whatever state you want regardless of which variant and point release installation image of 16.04 you use. However, doing things manually is of course not the same as being automatic.

So are you saying they won't make any more alternate releases for future releases?

Yes. It was that way for the 14.04 LTS, too.