F# 1.9.4 Now Available: Making F# Simpler and More Consistent

 [ Note: we have made a minor update to 1.9.4 called The download links below point to this release. If you need go to our downloads page. ]


 [ Note: download links updated to point to the MSI correctly ]


We’re very glad to announce the release of F# 1.9.4, the Spring Refresh of F#, uploaded to the Microsoft Research download site yesterday! (MSI download, ZIP, detailed release notes) (Ok, ok, apologies to our antipodean users where it’s actually autumn… In any case, on with the show!)


This release of F# has much the same shape and form as earlier releases of F# from MSR. As I hinted in April, our focus for this release has been on polishing and simplifying the language and libraries, particularly with regard to making certain details more regular and consistent. Much of this has been driven by user feedback, and we’d like to say a big thank you to for all the feedback we’ve got from hubFS users, the F# list, F# users at Microsoft and our growing number of commercial users, particularly our friends at the financial institutions using F#. Also a thank you to those community members who helped us by installing early releases of this version.


Some of the highlights of the language streamlining we’ve done in this release include

  • More consistent, symmetric operator overloading

  • Use named and optional arguments in conjunction with COM methods (gives simpler use of Excel, Word APIs etc.)

  • Additional nullness checking

  • Completing the object model (sealed, abstract class attributes and many other details have been addressed)

  • Performance optimizations in the F# core library

  • Improvements to the F# Interactive Window in Visual Studio

  • Over 100 bug fixes , many based on user feedback

Addressing items like these go a long way to transitioning the language into a stabilized, productization mode. Our overall goals, as always, are to integrate the succinctness, efficiency, expressivity of typed functional programming into the foundational set of tools that people use as part of .NET programming, while ensuring that language is simple-to-use and has great tool support.


The detailed release notes can be found here. This release doesn’t include many of the investments we’ve been making in Visual Studio tools – we’ll be rolling those out over the rest of the year as we move into CTP and beynd.


There have been numerous changes and enhancements in this release, documented below. These may cause you to see additional deprecation warnings or errors. We’d be particularly grateful if you could report any compilation failures, and if possible reduce them to a minimal repro for us.


Many thanks & enjoy your F# work!


Don, James, Luke, Brian, Jomo, Chris, Matteo, Santosh and Laurent


Comments (18)

  1. namin says:

    Is there going to be a new specification document matching this release?

    Thanks. ~n

  2. MichaelGG says:

    Awesome, thanks. Keep up the great work. I can’t wait for this to go more or less RTM so we can use it in production :).

  3. colder says:

    MSI and ZIP are same address

    There is some problem when I install on VS2008 via .bat

  4. Kudos to Don and the F# team! I already installed (and solved a little problem) with the new version. Just a small correction, the URL for the MSI installer is http://research.microsoft.com/research/downloads/Details/7ac148a7-149b-4056-aa06-1e6754efd36f/Details.aspx . Keep up the great work!!!

  5. En el camino de pasar de lenguaje de investigadores a lenguaje comercial de F#, Don Syme acaba de anunciar

  6. In its way from research language to commercial language, Don Syme just announced that, silently, on

  7. Mike says:

    Will the #light compiler directive be in the final release too?

  8. I missed this as I was doing a lot of work at the time (was release a few days back) as via Don’s blog

  9. Isaac Gouy says:

    Has anyone tried/succeeded in getting F# 1.9.4 to work with Mono 1.9.1?

  10. Isaac Gouy says:

    How can I get hold of ZIPs for previous F# versions? (The download page seems only to show the latest version.)

  11. leo says:

    Now FSharp is very powerfull language for functional/imperative/object-oriented program.But in the world,logical Paradigm languages are powerfull too, Constraint Programming is very good for computer algebra programming and symbolic computation programming.If add logical Paradigm in F#,F# is the first choice for numeric and symbolic computation programming.Now,there have a language Mozart-OZ hold all the paradigm functional/imperative/object-oriented/logical,but it have less lib for GUI and graphics like F# have .net lib and DirectX.So,if F# add some logical program elements,it will be the most perfect programming language in the world.

  12. I’ve just updated the links on the F# manual pages to point to the updated draft language specification

  13. Don, this version no longer works on Mono. Could you suggest a work around? –


    – fellow MSFT employee (sridhr)

  14. The F# team at Microsoft Research and Microsoft are currently working hard towards our planned CTP…