sure, but what always puzzled me is the close connection between a texmf tree and binaries; The fmt files will still embed pool checksums (among other things) so can't be arbitrarily swapped around with different binaries. Other than that, I think it would basically work to use a binary from one release and a tree from another, not that I've ever tried it (or see much reason to). Obviously 99% of the macros are independent of the particular binary. this may have changed now that we no longer have a dependency (i.e. no pool file any more) Indeed, that is a good advance. while maybe we can drop part of that history (say that all pascal sources are turned into c ... that would simplify things, wouldn't it?) It sure would, but knuth's tex & mf, plus omega and aleph will never be converted. So as long as we distribute Knuth's tex ... BTW, do you think aleph can become a symlink to luatex?! karl