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 Xen API Libs is a set of libraries and utilities in
-[OCaml](http://caml.inria.fr/ocaml/) that are used by
+[OCaml](http://caml.inria.fr/ocaml/) 3.12 that are used by
 [xapi](https://github.com/xen-org/xen-api). The libraries are a
 component of the Xen Cloud Platform (XCP) project.