do Microsoft monthly quality security rollups include previous-monthly releases? For example, if you skip march rollup and install april's?
For Windows 10, updates are cumulative. In October 2016, all patches to Windows 7 and 8.1 became cumulative as with Windows 10. The ability to download and install individual updates were removed as existing updates were transitioned to this model. Source: Wikipedia
I interpret this as if you will get March's update too if you install April's.