OpenGL 4.2, backwards compatible to OpenGL 1.0 (1992)
OpenGL ES, not backwards compatible with OpenGL.
There's an obvious parallel here of APIs being compatible within themselves but not across boundaries between major architectural revisions intended to throw out cruft and target new environments.
This line of reasoning is utterly absurd. They are different APIs with different names. The specifics of the substrings they have in common and the format of the substrings that differ is utterly irrelevant.
OpenCL is a different API from OpenAL, Cocos-2d is an API for an entirely different language than Cocos-2d-x, the Cocoa API is wildly incompatible with Cocoa Touch. Horrors!
You determine whether or not two APIs are compatible (or even striving to be the same kind of API) by reading the documentation, not by applying stupid heuristics to common substrings in their names.
X11 wasn't deprecated in 1987, that's when it was released. So far as I know, X11 hasn't been deprecated.
Side-note: Win16 (called "the Windows API" back then) actually predates X11 (though not previous versions of X) since Windows 1.0 was released in November 1985.
