Aliens. For real this time.

[Alex]

It isn't so much that they think that life could only happen in certain very narrowly defined ways as that there are chemical realities that make some possible biochemistries much more unlikely to actually happen.

So the news isn't so much that some deviation is possible it is in the fact that it has actually be discovered in the wild. Theorists have worked out biochemistries much more divergent (such as silicon based as opposed to carbon based) systems. What this discovery does is more play with the assumed odds of various lifeforms (when there's only one biochemical system proven to work in the wild, it makes sense that you look for conditions appropriate to that one).