I don't see it in my preferences. Anyone else see it in 188.8.131.521?
I have it in my copy, build 361, working normally!
It's still in the help file too.
Did you uninstall the pre-release FM and the Preferences before installing the release version? It's not there, as Stefan says, in my 184.108.40.2061 version.
Interesting that no mention of this feature being removed has been made in any of the documentation nor in any of the pre-release sessions.
I saw a similar behavior with the Special menu...
Try deleting your preferences (the 14 directory, as in C:\Users\Matt\AppData\Roaming\Adobe\FrameMaker\14) and restarting.
there is no FrameMaker XML Author (2017 release). This also means, that there is no option to switch to FM XMLA in FrameMaker (2017 release).
The last release is FrameMaker XML Author 2015.
Please stay tuned for more details to follow in the future.