MSXML4 is going to be kill bit-ed

MSXML4 is going to be kill bit-ed

  • Comments 27

Please read the latest entry on this at - We are NOT killbiting MSXML4




We are going to kill bit MSXML4 in the October – December timeframe of this year. Kill Bit applies to Internet Explorer only. After the kill bit , applications will not be able to create MSXML4 objects in the browser. Other Applications like C++ apps which are not killbit aware will continue to work with MSXML4.


We are announcing this in advance so that our customers get sufficient time to try their applications with MSXML6 and give us feedback on their experience.  Please email us at  with feedback/questions/concerns.





We are going to kill-bit MSXML4 to ensure a secure browsing experience for our customers. We are planning to also remove MSXML4 from the Download Center page within the next 12 months. Support for MSXML4 going forward will be restricted to high impact security issues only.


MSXML6 is the latest version available to MSXML customers today. This is where all the functionality, performance and security improvements are going in. In addition MSXML6 provides improved W3C compliance and increased compatibility with System.XML in .Net. The recommendation for MSXML customers is to program using MSXML6 and upgrade apps using older versions to MSXML6.



We strongly encourage everyone to start using MSXML6 SP1.MSXML6 SP1 is now available for all supported downlevel platforms and can be downloaded from


MSXML Supported Versions:


We addressed this in a blog entry


The  summary is

MSXML6  - Should be your first choice. This is the MSXML version that will be carried forward. MSXML6 shipped with Vista and we are working on getting this in downlevel OS Service Packs

MSXML3 – This has the advantage of having shipped with every supported OS .We are committed to keeping MSXML3 robust and stable but won’t be adding any functional improvements.

MSXML4  - This is in maintenance mode with a very high bar for fixes approaching End of Life.

MSXML 5 –  Exclusively meant for Office. Do not take any dependencies on it.


MSXML4 & 6 Differences and Compatibility:


Key changes introduced between MSXML4 and MSXML6 and migration are described in the blog entry at




We believe this is the best plan for MSXML customers going forward – avoids confusion regarding multiple versions, ensures a safe browsing experience when using MSXML and provides a path to use future functional improvements . If you run into issues with the migration or have questions/feedback feel free to contact us at . All of the MSXML team is on this alias eager to hear your feedback and assist with the migration.





  • According to the XmlTeam blog here MSXML4 is destined for a rather abrupt end. If you are using MSXML4

  • Our XML team announced this morning that, a s a part of our MSXML4 End of Life plan, we will kill bit

  • The Microsoft XML team has announced MSXML4 will be kill bit-ed in IE in the October - December 2007

  • MSXML6 SP1 fails to install on my Windows XP Professional workstation (actually a laptop).  I have installed Windows installer 3.1 and I have stopped all services, including those specific to SQL Server 2005.

    Each time the installation runs, it fails with a popup dialog box indicating "a netwok error occurred while attempting to read from the file <path name to the msi file on my sytstem>"

  • Hi Conrad,

    Please try saving the msi to your machine and running it locally. And let us know if you run into any issues with that.



    MSXML Team

  • And when might a 'kill bit' be applied to MSXML6 so we can decide whether to use it and for what to use it?

  • We are not planning to kill-bit Msxml6 at all. Msxml6 is here to stay.


    Umut Alev

    MSXML Team

  • To amplify Umut's point a bit -- The point of killbitting MSXML4 is to encourage people to migrate to MSXML6 so that they have a solid foundation going forward. There are no plans for an MSXML7, so this isn't something we're going to ask you to do all over again in a couple of years.

  • According to this post by the Microsoft XML team , MSXML 4.0 is going end of life near the end of 2007

  • Why is it going end of life near the end of 2007?

  • "kill bit-ing" is not "end of life" in Microsoft-ese.   The kill bit prevents a component from running in IE, it does not prevent it from being used in an application. See for more information.  The end of life plan is a much longer term process; the kill bit is just a nudge in that direction.

    All this is being done to reduce the cost and confusion for all of us caused by having so many supported versions of MSXML around at once. As of right now, we do need to support MSXML3 and MSXML6, but MSXML4 doesn't have any significant functionality that one of the others does not.

  • Jeremy Dallman here with some important information from the MSXML team to the IE development community.

  • Jeremy Dallman here with some important information from the MSXML team to the IE development community

  • MS are going to push out an IE specific kill-bit for MSXML4 in October. More information here:

  • Please note that MSXML 6 does not have a CAB installer, which makes it impossible to use in a browser application with respect to automatic download and instantiation.  MSXML 4 is the latest XML version that has a CAB installation.  PLEASE do us all a favor and provide a CAB installer so that we can start to use MSXML6, and please do this before you kill-bit MSXML4.  These are important considerations to be made.

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