A quote from the FAQ section of the link below:
What updates does this release replace?
This security update replaces a prior security update. The security bulletin ID and affected components are listed in the following table.
Bulletin ID Microsoft XML Core Services 4.0 Microsoft XML Core Services 6.0
Note This security update only replaces the MS06-061 security update for Microsoft XML Core Services 4.0 and Microsoft XML Core Services 6.0 as both Microsoft XML Core Services 3.0 and Microsoft XML Core Services 5.0 are not affected.
I'm not quite sure what you mean by "remove" in regards to the older version, but there's no need to remove anything.. The new version of the update replaces the old.
Hope this helps.
In Control Panel Add/Remove Programs I have two entries:
MSXML 4.0 SP2 (KB925672) Size 256MB
MSXML 4.0 SP2 (KB927978) Size 256MB
Question is can I remove the older Security Update (KB925672)? Nothing was mentioned in the download about removal. Not completely sure I had it before but assume as much. Update did not remove or replace it.