La noticia en InfoQ:
Back in March we reported that Microsoft was going to "killbit" MSXML 4. Due to its wide use and a lack of a suitable replacement, they have rescinded that decision.
Non-critical support for MSXML 4 ended a long time ago. However, the replacement, MSXML 6, lacks CAB support, which in turn makes switching to it more difficult than necessary.
CAB files are compressed files similar to ZIP, but specifically designed for Windows OS and Software components. They can be signed like ActiveX components, making them a primary means for deploying extensions to Internet Explorer.
Early responses to this are not favorable. Complaints are centralized around Microsoft waiting until just before the cut-off date to reverse their decision and complaints that lack of CAB support was a well-known issue that should have been addressed months ago.
For the time being, security issues will be addressed in MSXML 4 while new features and performance enhancements will only be given to MSXML 6. Microsoft's XML team has also promised to better integrate MSXML 6 into the OS deployments, presumably via Windows Updates and future service packs. There is no word on how long this reprieve will last or when MSXML 6 will finally be fully supported.
Es conveniente leer la nota original de la que parte InfoQ.
Habrá que prever soporte de más parsers donde corresponda...(tarea a realizar). Como sucede en general, probablemente la compatibilidad hacia atrás será árdua. En algún momento hablaremos sobre las política de actualizaciones...