How do you know when a Microsoft hotfix has been obsoleted by a newer patch?

Solution 1:

Those two KB's are not for the same issue. While someone somewhere may indicate that one obsolete's the other because it worked in their scenario, it is not necessarily the case.

Microsoft include information on associated KBs in the Introduction portion of the KB or the Resolution section, such as with KB948609 (can't add a link as I'm new). As with KB924895, there is usually a section that states something like:

Hotfix replacement information
This hotfix does not replace any other hotfixes.

I don't know that this is used consistently though, and of course, Microsoft has no control over what people write in forums on the Internet.

Solution 2:

If you compare file information for KB929774 and KB940252 (for the same base OS and SP level), you will see that these hotfixes include exactly the same set of files, but all file versions in KB940252 are newer than KB929774. This means that installing KB940252 after KB929774 will give the same result as installing KB940252 alone, so in effect KB940252 replaces KB929774 (and actually includes all changes from KB929774 and any previous hotfixes for these files).

Additional information:

• Windows Hotfixes and Updates - How do they work?
• GDR, QFE, LDR... WTH?