Not sure if this affects anyone but thought I’d post the info for others just in case.
Effective as of the May 2016 security bulletin release, all Windows updates will be available only via the Microsoft Update Catalog (http://catalog.update.microsoft.com/), and will no longer be available on the Microsoft Download Center
(http://download.microsoft.com/). Making the updates available from only one location simplifies the process for our customers of finding and downloading security updates.
http://seclists.org/microsoft/2016/q2/6
(Search for “Other Information” near the middle)
This was posted last week on seclist.org for a few Microsoft updates, but I couldn’t find anything official from Microsoft. One of my colleagues contacted our MS rep, and he confirmed that this change is happening and that Microsoft is working on an official announcement. Our MS rep also said the bulletin links will then point to the Update Catalog.
Not sure if the old download links will still work or point to the Catalog, but it may be worth keeping in mind just in case you have old links in your custom content or if you notice any weird download behaviors in any Windows Updates content.