I kept feeling like I was reading the same thing over and over and just not finding out what exactly Amazon is doing now that it won't be able to do in the future. Skimming the links to the blog post and FAQ didn't help much.

Whatever it is it's pretty deep in the weeds. It looks like the intent is for most users to be unaffected; non-AWS cloud providers to be unaffected; even AWS's Elastic Cloud to be unaffected; but AWS has to stop doing something with specific regard to Elastic Search and I can't figure out what it is.