We have standardized on the cygwin (64-bit) platform at my workplace. The latest version of ocaml available for this platform in the cygwin-package tool is 4.04.2. This is also the latest version which has worked without problems for me. Later versions can be be installed using opam, but as soon one tries to use the compile suit or install extra libraries with opam there are problems connected to loading shared libraries.  Some googling gives that there is a problem concerning flexdll/flexlink causing this. I hope someone can give me more information on this. Is the cygwin64 platform presently abandoned or is this worked on or planned to be fixed in some future version (which) ? Is there a plan to update the version at the cygwin package tool soon?