Microsoft has announced that it will be shifting to monthly rollup updates for Windows 7 and Windows 8 as of October 2016. The company also announced that this monthly patch model would apply to Windows Server 2008 R2, Windows Server 2012 and Windows Server 2012 R2 as well.
In simple terms, this change means that what would have been delivered as multiple individual patches before will now be rolled out once a month in a single package. According to Microsoft's explanation, this should reduce fragmentation brought about by the current model, through which different PCs could have different sets of updates installed.
The new model also has the added benefit of always only requiring one update to be downloaded. Microsoft explains:
The Monthly Rollup will be published to Windows Update (WU), WSUS, SCCM, and the Microsoft Update Catalog. Each month's rollup will supersede the previous month's rollup, so there will always be only one update required for your Windows PCs to get current. i.e. a Monthly Rollup in October 2016 will include all updates for October, while November 2016 will include October and November updates, and so on. Devices that have this rollup installed from Windows Update or WSUS will utilize express packages, keeping the monthly download size small.
Microsoft also notes that its goal is for the updates to become eventually "fully cumulative," containing all of the patches shipped "since the last baseline." That process will take place over the course of the next year. In a broader sense, this could be seen as direct a move by Microsoft to push those organizations still on an older OS towards upgrading by removing the unique ability to cherry-pick updates.
Lastly, Microsoft says that it will also push a monthly "Security-only" update that will only contain security patches for that month. This will be released separately from Windows Update via WSUS, SCCM, and the Microsoft Update Catalog.