Hello we have just done patching of our customer's servers. We noticed atound half of windows 2016 did not download and install this big update KB4480961. The customer's security department is worried hwy is that so. I wonder if that's a bug or something reasonable makes this patch not applicable/needed for these servers? The difference between those which got this update is they don't have KB4483229. Does it work that way that after installing KB4480961 the KB4483229 disappears from the get-hotfix list?
Microsoft explained this:
The Delta package for this update assumes you have deployed the December 19th security update (KB4483229). If you have not deployed the December 19th security update (KB4483229), then you must apply the Full Update for this release and cannot use the Delta package."*
In plain English: Cumulative means everything before it. Delta means a smaller package that contains only the fixes for the selected month. The delta updates are applicable to the computers that have cumulative or delta updates installed for the previous month.