It's not at all clear to me from reading CDR document 10 http://cdr.eurolisp.org/document/10/compiled-file-p.html what an ABI version is (as in "the argument identifies an ABI version which can be consumed by the implementation"). Further examples of abi-version (in particular, one which shows a possible input or output value rather than just piping the two together) would make this clearer.
- nick