Microsoft is going to cease its current practice of making all security updates available from both the Microsoft Download Center and the Microsoft Update Catalog.
In a very brief April 29 blog post,
company officials noted the coming change, which takes effect next Tuesday, May 10 -- which is Patch Tuesday. Moving forward, security bulletins will point to the Microsoft Update Catalog when updates are not listed on the company's Download Center website.
From Microsoft's post:
"Updates have historically been published on both the Microsoft Download Center and the Microsoft Update Catalog
and Security Bulletins linked directly to update packages on the Microsoft Download Center. Starting May 10, some updates will no longer be available from the Microsoft Download Center."
What Microsoft's blog post doesn't say is why the company is making this change.