MSXML4 to be Disabled in Late 2007


Internet Explorer Team Blog

MSXML4 to be Disabled in Late 2007

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Jeremy Dallman here with some important information from the MSXML team to the IE development community. The XML Team’s Blog has recently announced that they will be issuing a kill-bit for MSXML4 at the end of 2007 (October-December timeframe). Please read through the below post copied from the XML Team’s Blog and start validating your applications against MSXML6.

They have provided an email address to field your questions or concerns. Please don’t hesitate to contact them with your feedback.

Jeremy Dallman
Program Manager

[from the MSXML Blog]

As a part of our MSXML4 End of Life plan , we are going to kill bit MSXML4 in the October – December timeframe of this year. This kill bit applies to Internet Explorer only. After the kill bit, web applications will not be able to create MSXML4 objects in the browser. Applications which are not kill-bit 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 down-level 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.

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